vb.net - load image in picturebox quickly -


i have program shows previews of jpgs in small pictureboxes. loading of these images slow, , takes second each. because images big (8/9 mb). need load them quickly, example loading thumb of picture. avoid putting memory since there hundreds of pictures.

what advice on this?

thanks

you need resize pictures in advance.

creating tumbnails equally slow because need read whole file, before can start making tumbnail.

what is, windows, create tumbnail 'data base', store tumbs each picture. , use full size picture if needed.

so if have like,

picture001.jpg picture002.jpg picture003.jpg

create tumbs each one;

picture001.jpg picture001_tumb.jpg picture002.jpg picture002_tumb.jpg picture003.jpg picture003_tumb.jpg

so in loading of picuters detect, if _tumb.jpg there, if not create , store it. ofcourse, needs done in background worker, because need main app responsive...

you can use code, request icon windows shell;

imports system.runtime.interopservices imports system imports system.drawing imports system.drawing.imaging imports system.collections.generic imports system.text  ' http://www.vbforums.com/showthread.php?617626-how-do-i-extract-a-256x256-image-out-of-an-icon&highlight=ishellitemimagefactory  module getshellicon     <flags()> _     public enum siigbf         siigbf_resizetofit = 0         siigbf_biggersizeok = 1         siigbf_memoryonly = 2         siigbf_icononly = 4         siigbf_thumbnailonly = 8         siigbf_incacheonly = 16     end enum      public enum sigdn uinteger         normaldisplay = 0         parentrelativeparsing = &h80018001ui         parentrelativeforaddressbar = &h8001c001ui         desktopabsoluteparsing = &h80028000ui         parentrelativeediting = &h80031001ui         desktopabsoluteediting = &h8004c000ui         filesyspath = &h80058000ui         url = &h80068000ui     end enum      <comimportattribute(), guidattribute("bcc18b79-ba16-442f-80c4-8a59c30c463b"),     interfacetypeattribute(cominterfacetype.interfaceisiunknown)> _     public interface ishellitemimagefactory         sub getimage(byval size size, byval flags siigbf, byref phbm intptr)     end interface      <comimport()> <guid("43826d1e-e718-42ee-bc55-a1e261c37bfe")>     <interfacetype(cominterfacetype.interfaceisiunknown)> _     public interface ishellitem         sub bindtohandler(byval pbc intptr, <marshalas(unmanagedtype.lpstruct)>     byval bhid guid, <marshalas(unmanagedtype.lpstruct)> byval riid guid, byref ppv     intptr)         sub getparent(byref ppsi ishellitem)         sub getdisplayname(byval sigdnname sigdn, byref ppszname intptr)         sub getattributes(byval sfgaomask uint32, byref psfgaoattribs uint32)         sub compare(byval psi ishellitem, byval hint uint32, byref piorder     integer)     end interface      <dllimport("shell32.dll", charset:=charset.unicode, preservesig:=false)> _     public sub shcreateitemfromparsingname(<marshalas(unmanagedtype.lpwstr)> byval     pszpath string, byval pbc intptr, <marshalas(unmanagedtype.lpstruct)> byval riid     guid, <marshalas(unmanagedtype.interface, iidparameterindex:=2)> byref ppv ishellitem)     end sub      <structlayout(layoutkind.sequential)> _     public structure size         public cx integer         public cy integer         public sub new(byval cx integer, byval cy integer)             me.cx = cx             me.cy = cy         end sub     end structure      public function getshellicon(byval path string, mysiigbf siigbf, optional byval width integer = 256, optional byval height integer = 256) bitmap          dim ppsi ishellitem = nothing         dim hbitmap intptr = intptr.zero         dim uuid new guid("43826d1e-e718-42ee-bc55-a1e261c37bfe")          dim bs bitmap          shcreateitemfromparsingname(path, intptr.zero, uuid, ppsi)         directcast(ppsi, ishellitemimagefactory).getimage(new size(width, height), mysiigbf, hbitmap)         bs = system.drawing.bitmap.fromhbitmap(hbitmap)         bs.maketransparent(color.black)          return bs      end function  end module

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