How to crop and resize images | Adobe Photoshop 教學課程

Learn the basics of image resizing in Adobe Photoshop, including how to resize, crop, straighten photos, and more. AdobePhotoshop iPad功能 功能 神經濾鏡 天空取代 Photoshop筆刷 內容感知填滿 相片效果 學習與支援 比較計劃 免費試用 立即購買 Changetheimagesize 搜尋 Learnhowtoresizeanimage,cropandstraighten,andaddtotheimagecanvasinAdobePhotoshop. 您需要的項目 Getfiles Samplefilestopracticewith(ZIP,8MB) Resizeanimage Changethesizeofanimage. Let'stalkabouthowtochangethesizeofanimageinPhotoshop.Isuggestthatyoustartwiththisimagefromthedownloadablepracticefilesforthistutorial.I'dliketosetthesizeofthisimage,sothatit'sagoodfitforpostingtoaparticularwebsite,whereIhappentoknow,thattheidealimagesizeis900pixelswide.Beforeweresizethisimage,let'scheckhowbigitistostartwith.Inmostcases,you'llwanttostartwithanimagethat'sbiggerthanoratleastnotalotsmallerthantheresizedimagethatyouneed.That'sbecause,ifyouenlargeanimagealot,atsomepoint,itcanstarttolookblurry.I'llgodowntothestatusbaratthebottomoftheDocumentwindow,andI'llclickandholdonthedocumentsizeinformation.Inthesmallwindowthatpopsup,wecanseethatthisfileis1800pixelswideby1200pixelshigh.Sincewewanttoputitinaspotthat'sonly900pixelswideonourwebsite,thatmeanswe'llbescalingitdown.Toresizethisimage,I'llgouptotheImagemenu,andI'llchooseImageSize...ThatopenstheImageSizedialogbox.Ifyoulike,youcanmakethiswindowbiggerbygoingtothebottomrightcorneranddraggingout.Overontheleft,youcanseeapreviewoftheimageandontheright,arethecontrolsforchangingimagesize.There'salotofinformationhere,butyoudon'thavetoworkthroughallofit,particularlywhenyou'reresizinganimagethatwillbeviewedonthescreenasopposedtoprint.Asweareinthisexample.So,there'sjustacoupleofthingstocheckhere.First,makesurethatthisLinkiconison.Thisiswhatitlookslikewhenit'son.IfIclickit,thisiswhatitlookslikewhenit'soff.So,wewantiton,tomakesurethattheWidthislinkedtotheHeight,sothatwhenweresizetheimage,theoriginalproportionofwidthtoheightispreservedandtheimagedoesn'tlooksqueezedorstretched.Second,makesurethatthere'sacheckmarkinthisbox,theResamplebox.Whenthisboxischecked,you'retellingPhotoshopthatit'sOKtothrowawaysomepixelswhenitmakesthisimagesmaller.Orifyouweremakingtheimagebigger,toaddsomepixels.Andthird,takealookovertotherightoftheWidthandHeightfields,whereyoucanseetheunitofmeasurementthat'sbeingusedtoreportthedimensionsoftheimage.Bydefault,thisissettoinches.Butwhenyou'resizinganimageforuseon-screenaswe'redoinginthisexample,thecorrectunitofmeasurementisnotinches,it'spixels.So,I'mgoingtoclickoneitherofthese2menus,andchangeitfromInchestoPixels,andtheothermenuchangestoobecausetheWidthandHeightarelinked.Nowit'stimetochangethesize.I'llgototheWidthfieldandinsteadof1800I'lltype900.YoucanseethattheHeightfieldautomaticallychanged,anditchangedproportionately.Now,here'sabonustip:ifyouwantedanimagetohavedifferentproportions,say900by400,ratherthan900by600inthiscase,thebestwaytoachievethatwouldbetouseanothertool,theCroptool,whichwe'regoingtocoverinanothermovie.BeforeIclickOK,youmaybewonderingwhyIdidn'tchangetheResolutionfield.That'sbecausethisResolutionfieldisonlyrelevantwhenyou'repreparinganimageforprint.Whenyou'resizinganimageforon-screenuse,asinthisexample,thenumberinthisfieldreallydoesn'taffectthedimensionsoftheimage.So,youcanleaveitsettowhateverithappenstobe.So,aftermakingthosefewchangesintheImageSizedialog,wecannowcomedowntotheOKbuttonandclicktheretoclosetheImageSizedialogboxandtakeusbacktotheDocumentwindow.Ifyoulike,youcangobacktotheStatusbarandcheckthesizeoftheresizedimage.I'llclickandholdontheinformationthereandyoucanseethatwenowhavea900by600pixelimageinsteadoftheoriginalwhichwas1800by1200.Allthatislefttodo,istosavetheimage.I'llgouptotheFilemenu,andI'mgoingtochooseSaveAs...ratherthanSavebecauseIdon'twanttosaveovertheoriginal1800by1200pixelversion.So,intheSaveAsdialog,I'mgoingtogivethisversionanothername.Youcantypeanythingyouwanthere.I'mgoingtotype"Resize-web.jpg"formywebsizedversionofthefile.I'llleaveeverythingelseasitwasandI'llclickSave.I'llclickOKintheJPEGoptionswindow,andnowwe'redone.Sothat'showtoresizeanimageforon-screenuseinPhotoshop'sCCImageSizedialogbox.    Whatyoulearned:Toresizeanimage ChooseImage>ImageSize. Measurewidthandheightinpixelsforimagesyouplantouseonlineorininches(orcentimeters)forimagestoprint.Keepthelinkiconhighlightedtopreserveproportions.Thisautomaticallyadjuststheheightwhenyouchangethewidthandviceversa. SelectResampletochangethenumberofpixelsintheimage.Thischangestheimagesize. ClickOK. Settheresolution Changetheresolutionofanimage. Ifyouliketoprintimages,itcanbeusefulforyoutohaveabasicunderstandingofwhatimageresolutionmeansinPhotoshop,andhowtochangetheresolutionofanimagetoprepareitforprint.That'sdoneintheImageSizedialogbox.Ifyou'refollowingalong,let'sopenthisimage,thatyou'llfindinthepracticefilesforthistutorial.AndthengouptotheImagemenu,andchooseImageSize...IntheImageSizedialogbox,youcanseetheDimensionsofthisimagereportedinpixels.Whenanimageisstillonyourcomputer,that'showwemeasureitssize,inpixels.Butifweweretoprintthisimage,wewouldmeasurethesizeoftheprintininches,notpixels.DownhereintheResolutionfield,youcanseetheresolutionthat'scurrentlysetforthisimage,it's100.There'snothingspecialaboutaresolutionof100,it'sjustaroundnumberthatIpickedwhenIsetupthefileforthislesson.Now,whatdoesResolutionmeanhere?Well,ifyoureadacrossthislinefromlefttoright,youmaygetasenseofit.ThisistellingusthatresolutionisaparticularnumberofPixels/Inch,inthiscase100Pixels/Inch.Anotherwaytosaythat,isthatifandwhenyouprintthisimage,100pixelsoutofthetotal1800acrossandthetotal1200down,willbeassignedtoeveryprintedinch,horizontallyandvertically.Nowifyoudon'tlikemathproblems,youcanskipthenextpart,butifyouliketothinkofthisintermsofmath,here'sasimpleexample.So,themathproblemis:divide1800by100andyouget18.Thatmeansthatatresolutionof100pixelsperinch,thisfilewillprintat18inchesacross.Anditworksthesamewayvertically.Ifwedividethetotal,1200pixelsofheightintogroupsof100,thatgivesyou12groupsor12inches.So,theheightoftheprintedimagewillbe12inches.So,ifyouunderstandthatbasicconcept,nowyou'reprobablywondering,wellwhat'sthebestnumbertoputintheResolutionfieldwhenyou'repreparinganimageforprint?Unfortunately,there'snooneanswerbecausethatdependsonwhatprinteryou'reusing.Butassumingyou'reprintingathomeonatypicalinkjetprinter,it'sfairtosay,thataresolutionofabout300pixelsperinchwilldo.IfIweretoprinttheimagewithonly100pixelsperinch,itmightlookOK,butifyougotreallyclosetoit,itwouldn'tlookitsbest.Becausemydesktopinkjetprinterreallyneedsaround300pixelsperinch.Sohowdoyougoaboutchangingtheresolutionofaprintedimageto300pixelsperinchinthisdialoguebox?ThefirststepistomakesurethattheResampleboxisunchecked.Becauseifwe'rejustchangingtheresolution,weprobablydon'twanttochangethetotalnumberofpixelsinthefile.Andthat'swhatResampledoes.So,let'ssaythatwewantthetotalnumberofpixelsinthefiletoremainat1800by1200.Wejustwanttoreallocatethemintogroupsof300ratherthangroupsof100.So,whatI'mgoingtodoistype300intheResolutionfield.Spoileralert:whenIdothat,thenumberofinchesintheWidthandHeightfieldswillchangetoo.So,let'sgoaheadandtype300here.AndsureenoughtheWidthandHeighthavechangedfrom18inchesand12inches,to6inchesby4inches.Andthat'sthesizeatwhichthisimagewillprintwiththenecessaryresolutiontomakethebestprint.I'mdonehere,soI'mgoingtoclickOK.ThatclosestheImageSizedialogboxandtakesmebackouttotheDocumentwindow.AndhereIhaveanimagereadytosaveandprintat6inchesby4inches,with300pixelsineveryinch.    Whatyoulearned:Tochangeimageresolution ChooseImage>ImageSize.Resolutioninthisdialogboxmeansthenumberofimagepixelsthatwillbeassignedtoeachinchwhentheimageisprinted. Leavewidthandheightsettoinchesforprinting. DeselectResampletopreservetheoriginalnumberofimagepixels. IntheResolutionfield,setthenumberofpixelsperinchto300forprintingtoatypicaldesktopinkjetprinter.Thischangesthenumberofinchesinthewidthandheightfields. ClickOK. Cropandstraightenanimage UsetheCroptool. TheCroptoolisoneofPhotoshop'sCCmostusefultools,particularlyforthoseofyouwhotakelotsofphotographs.Youcanuseittoimproveacompositionandtostraightencrookedphotos.I'veopenedthisphotofromthepracticefilesforthistutorial.So,IcanshowyouthebasicsoftheCroptool.I'llstartbyselectingtheCroptoolhereintheToolspanel.AssoonasIdo,youcanseethisborderaroundthewholeimage.That'stheCropbox.I'llmovemycursoroveranyofthecornersoranyoftheedgesoftheCropboxanddragtoreshapethatbox.So,inthiscase,Imightdragitwayintocreateaverydifferentcompositionthantheoriginalphotograph.Asyoucreateyourcrop,Photoshopshowsyouapreviewwiththeareastobecroppedawayshadedingray.Thatwayyoucanevaluatewhatitisyou'reabouttoeliminatebeforeyoufinalizethecrop.Now,beforeIfinalizethiscrop,IwanttogouptotheOptionsbartoshowyouanimportantoptionthere.AndthatisDeleteCroppedPixels.Thatoptionischeckedbydefault.Iusuallyliketouncheckthat.BecausewhenDeleteCroppedPixelsischecked,ifyoufinalizethecropandsavetheimage,you'llpermanentlydeletethecroppedawaypixels.But,withthisoptionunchecked,youcanbringbackthecroppedawaypixelsatanytime.Let'sgiveitatry.I'mgoingtofinalizethiscropbygoingovertothebigCheckmarkintheOptionsbarandclickingthere.Now,thereareotherwaystofinalizeacrop,butIlikethiswaybecauseit'sverysimple.Sonowyoucanseethephotowiththecropapplied.Let'ssaythatI'mdoingsomethingelsewiththeimageandthen,IchangemymindaboutthewayI'dcroppedit.Atanytime,IcangobackandselecttheCroptoolandthenclickontheimageagain,andallthepixelsthatIcroppedawayappearbackinviewandIcanchangemycrop.ThistimeImightincludesomeofthosecroppedawaypixels.Bytheway,youmayhavenoticedthatthere'sagridofverticalandhorizontallinesontopofmyphotoasIusetheCroptool.Thisoverlaypresentsaclassiccompositionaltechniqueknownastheruleofthirds.Theideaofthistechniqueisthatifyouplacetheimportantcontentinanimageattheintersectionofanyofthesehorizontalandverticallinesyoumayimprovethecomposition.Let'sgiveitatrywiththisimage.I'mgoingtoplacethebouquetrightatthisintersectionbyclickingontheimageanddraggingandplacingithere.AndthenImightreshapethecropboundaryalittlemore,pullingitintighteronthisbouquet.AndthenI'llclicktheCheckmark.Again,I'mgoingtoclickontheimagewithmyCroptooltotrytofine-tunethiscropalittlemore.Inoticethatthisimageisalittlecrooked,especiallydownhereatthetable.OneofthethingsyoucandowiththeCroptoolisstraightenanimage.Thereareacoupleofwaysyoucandothat.Youeithercanmoveyourcursoroutsideofoneofthecornersandmanuallytrytodragtostraightentheimage,andthisgridappearsthathelpsyoudothat.Iprefertheautomaticmethod.So,I'mgoingtoundo,that'sCommand+ZontheMac,Ctrl+ZonthePC.So,theimageiscrookedagainandthenI'llgouptotheOptionsbarandI'mgoingtousetheautomaticstraightentool.I'llclickonthattooltoselectitintheOptionsbarfortheCroptool.I'llmoveintotheimage,andthenI'mgoingtoclickalongtheedgeofthistable,holdmymousedown,anddragalittlewayfurtheralongthatedge.Nowyoudon'thavetogoallthewayalongwiththeedge.Sometimesjustalittlebitwilldothetrick,likethis.AndPhotoshopusesyourlineasaguidetorotatetheimagesothatthecontentlooksstraight.I'mgoingtofine-tunethiscropalittlemore,maybebringingupthisedgeandmaybemovingthebouquetoverabittoputitrightinthecenter.AndthenI'mgoingtogouptotheOptionsbarandclicktheCheckmarktofinalizemycrop.SothosearesomeofthebasicsoftheCroptool.IhopeyougivethesetechniquesatrytoworkonyourowncompositionsinPhotoshop.    Whatyoulearned:Tocropandstraightenanimage SelecttheCroptoolintheToolspanel.Acropborderappears. Draganyedgeorcornertoadjustthesizeandshapeofthecropborder. Draginsidethecropbordertopositiontheimageinsidethecropborder. Dragoutsideacornerofthecropbordertorotateorstraighten. ClickthecheckmarkintheoptionsbarorpressEnter(Windows)orReturn(macOS)tocompletethecrop. Expandthecanvas Addsomespacetothedocumentcanvas. Theremaybetimeswhenyouwanttoaddtoyourdocumentcanvas,sothere'smoreroomtoaddelementsliketextorimagestoyourdesign.YoucandothatbyusingtheCanvasSizecommandwhichwe'lllookatinthislesson.Ifyou'refollowingalong,youcanusethisimagefromthepracticefilesforthistutorialoranimageofyourown.Toaddtothecanvasaroundthisimage,I'llgouptotheImagemenu,wherethereisaCanvasSize...commandrightbelowtheImageSize...command.Now,justtokeepthese2straight,theImageSizecommand...,whichwelookedatinanothervideointhistutorial,worksdifferentlythantheCanvasSize...command.UnlikeImageSize...,CanvasSize...doesn'tchangethesizeofyouractualphotosorotherartworkorimagesinacomposition.Itjustletsyouaddspacearoundthoseitems.So,let'sselectCanvasSize...AndthatopenstheCanvasSizedialog.Atthetopofthisdialog,youcanseetheWidthandHeightofthisimageinInches.AnddownhereyoucanaddtotheWidthofthecanvasoraddtotheHeightofthecanvasorboth.AndthosefieldsaresettoInchesbydefaultalso.Butwhenyou'repreparinganimageforonlineuse,ratherthanforprint,itmakesmoresensetochangethisunitofmeasurementtoPixelsbecausethat'sthewaywemeasureandtalkaboutthesizeofimagesonscreen,asyoulearnedearlierinthistutorial.So,I'mgoingtochangeeitheroneofthesemenusfromInchestoPixels.Andtheothermenuchangestoo.Ifyouknowthetotalwidthinpixelsthatyouwanttheimagetobeafterexpandingthecanvas,youcouldtypethatnumberhereintheWidthfield.Butit'softeneasiertojusttellPhotoshophowmanypixelstoaddtothecanvaswithoutworryingaboutwhatthetotalwillbe.Todothat,comedownhereandclicktheRelativecheckbox.ThatsetsthenumberintheWidthandHeightfieldsto0.Andnow,IcantypeinthenumberofpixelsthatIwanttoaddtothecanvas.So,let'ssaythatIwanttoadd400pixelstothewidthofthecanvas.I'lltype400here.IfIwantedtoaddtotheheightofthecanvas,Icoulddothattoo.I'mjustgoingtoleavethatat0fornow.AndthenI'llclickOKtoapplythat.AndoutintheDocumentwindow,youcanseethatPhotoshopaddedcanvastoboththeleftandtherightsidesofthisphoto.Whatitdidwassplitthe400pixelsofextrawidththatIaskeditfor,into200pixelsontherightand200pixelsoverhereontheleft.Well,whatifIwantedtoaddcanvastojustonesideofthisimage.Let'ssayoverheretotherightside.That'sdoneslightlydifferently.So,let'sundowhatwe'vedonesofar,trythatinstead.I'llpressCommand+ZontheMac,Ctrl+ZonaPCtoundo.AndI'llgobacktotheImagemenuandchooseCanvasSize...again.ThefirstthingI'mgoingtodohereistocheckthattheWidthandHeightfieldsarestillsettoPixels.Andthey'renot,they'verevertedtothedefaultInches.Soagain,I'llchangethosemenustoPixels.AndI'lldoublecheckthatRelativeischecked.AsIsaid,Iwanttheaddedcanvastoappearjustontherightsideofthisimage.Todothat,I'llgodowntothisanchordiagramandI'mgoingtoclickonthemiddleboxontheleftsideofthisdiagram.WhatthatdoesistellPhotoshoptopinoranchortheimagetotheleftsideofthecanvas,andputtheextracanvastoitsright.SonowI'mgoingtogouptotheWidthfield,andI'mgoingtotypeinthenumberofpixelsthatIwanttoaddtotherightsideofthisimage.Let'sadd800pixels.AndclickOK.Andthat'sexactlytheeffectthatIwanted.Youprobablynoticedthatsofar,mycanvasextensionshaveallbeenwhite.Butyoucancontrolthecolorofyourcanvasextension,hereintheCanvasSizedialog,usingtheCanvasextensioncolormenuhere.Bytheway,ifyou'reworkingonanotherimage,andyou'renotonaspecialbackgroundlayer,asweareinthisimage,thenyourCanvasextensioncolormenuwillbeunavailableandthecanvasthatyouaddwillbetransparent.ItwillappearlikeagrayandwhitecheckerboardinPhotoshop.I'mjustgoingtoclickCancel.And,ifIwanttosavethisimage,I'llgototheFilemenuandI'llchooseSaveAs...,soIdon'tsaveovermyoriginal.Sothat'showyoucanaddspacetoyourdocumentcanvas,soyouhavesomeextraroomtoaddmoreimageelements.    Whatyoulearned:Tochangecanvassize ChooseImage>CanvasSize Toaddacanvas,entertheamountofwidthandheighttoadd.Measurewidthandheightinpixelsforonlineuseorininchesforprint. SelectRelative,andthenselectananchorpointinthecanvasdiagram.Thearrowspointtothesideswherethecanvaswillbeadded. ClickOK.   Backto: GettoknowPhotoshop |Upnext: Workwithlayers   01/13/2020   Presenter:JanKabili Photographer:MartinHoang Florist:KianaUnderwood PatternMaker:WilOrtanez 現正檢視 下一張 再次檢視 其他教學課程 此頁面對您有幫助嗎？ 是 否 無意見 送出 按一下「送出」即代表您接受Adobe使用條款。

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