More and more internet sites prefare using with PNG files instead of JPG or GIF.
For many reasons, sometimes Internet explorer unable to view png files.
If the rason is That PNG file contains one or more zero-length IDAT chunks you may use this link
to download Microsoft Hotfix and solve the problem:
http://support.microsoft.com/kb/897242

In other cases try the following methods:

1. Enable Scripts in Firewall

the configurations in your Firewall program (Like Symantec Endpoint etc) may block scripts
(Active scripts, Scriptlets, Java applet, ActiveX control) sometimes used by webmasters.

2. Enable scripts in Internet explorer

A. Open Internet explorer 7
B. Go to Tools – Internet Options- Security tab. change “Internet zone" to “Medium” or reset the zone to “Default” level and save.


3. Problem may occur because “Show Pictures” option in Internet explorer 7 is not selected

A. Open Internet explorer 7
B. Go to Tools – Internet Options – Advanced tab, slect “Show pictures” under the “Multimedia” menu and press OK.

5.Delete Internet explorer cache

A. Open Internet explorer 7
B. Go to Tools – Internet Options – General – delete – delete "temporary internet files" and "cookies".

If none of the methods worked, try the following reg file on your own risk (be sure to backup registry first).

copy this  to a text file and save it as File_Name.reg:

"Windows Registry Editor Version 5.00

Start copy here:
—————————
[HKEY_CLASSES_ROOT\.PNG] "PerceivedType"="image"
@="pngfile"
"Content Type"="image/png"

[HKEY_CLASSES_ROOT\.PNG\PersistentHandler] @="{098f2470-bae0-11cd-b579-08002b30bfeb}"

[HKEY_CLASSES_ROOT\pngfile] @="PNG Image"
"EditFlags"=dword:00010000
"FriendlyTypeName"=hex(2):40,00,25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52,\
  00,6f,00,6f,00,74,00,25,00,5c,00,73,00,79,00,73,00,74,00,65,00,6d,00,33,00,\
  32,00,5c,00,73,00,68,00,69,00,6d,00,67,00,76,00,77,00,2e,00,64,00,6c,00,6c,\
  00,2c,00,2d,00,33,00,30,00,35,00,00,00
"ImageOptionFlags"=dword:00000003

[HKEY_CLASSES_ROOT\pngfile\CLSID] @="{25336920-03F9-11cf-8FD0-00AA00686F13}"

[HKEY_CLASSES_ROOT\pngfile\DefaultIcon] @="shimgvw.dll,2"

[HKEY_CLASSES_ROOT\pngfile\shell] @="open"

[HKEY_CLASSES_ROOT\pngfile\shell\open] "MuiVerb"="@shimgvw.dll,-550"

[HKEY_CLASSES_ROOT\pngfile\shell\open\command] @="rundll32.exe C:\\WINDOWS\\system32\\shimgvw.dll,ImageView_Fullscreen %1"

[HKEY_CLASSES_ROOT\pngfile\shell\open\DropTarget] "Clsid"="{E84FDA7C-1D6A-45F6-B725-CB260C236066}"

[HKEY_CLASSES_ROOT\pngfile\shell\printto]

[HKEY_CLASSES_ROOT\pngfile\shell\printto\command] @="rundll32.exe C:\\WINDOWS\\system32\\shimgvw.dll,ImageView_PrintTo /pt \"%1\" \"%2\" \"%3\" \"%4\""

[HKEY_CLASSES_ROOT\SystemFileAssociations\.PNG] "ImageOptionFlags"=dword:00000003

[-HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.PNG]

[-HKEY_CLASSES_ROOT\Mime\Database\Content Type\image/x-png]

[-HKEY_CLASSES_ROOT\Mime\Database\Content Type\image/png]

[HKEY_CLASSES_ROOT\Mime\Database\Content Type\image/x-png] "Extension"=".png"
"Image Filter CLSID"="{A3CCEDF7-2DE2-11D0-86F4-00A0C913F750}"

[HKEY_CLASSES_ROOT\Mime\Database\Content Type\image/x-png\Bits] "0"=hex:08,00,00,00,ff,ff,ff,ff,ff,ff,ff,ff,89,50,4e,47,0d,0a,1a,0a

[HKEY_CLASSES_ROOT\Mime\Database\Content Type\image/png] "Extension"=".png"
"Image Filter CLSID"="{A3CCEDF7-2DE2-11D0-86F4-00A0C913F750}"

[HKEY_CLASSES_ROOT\Mime\Database\Content Type\image/png\Bits] "0"=hex:08,00,00,00,ff,ff,ff,ff,ff,ff,ff,ff,89,50,4e,47,0d,0a,1a,0a

[HKEY_CLASSES_ROOT\CLSID\{A3CCEDF7-2DE2-11D0-86F4-00A0C913F750}] @="CoPNGFilter Class"

[HKEY_CLASSES_ROOT\CLSID\{A3CCEDF7-2DE2-11D0-86F4-00A0C913F750}\InProcServer32] @="C:\\WINDOWS\\system32\\pngfilt.dll"
"ThreadingModel"="Both"

[HKEY_CLASSES_ROOT\CLSID\{A3CCEDF7-2DE2-11D0-86F4-00A0C913F750}\ProgID] @="PNGFilter.CoPNGFilter.1"

[HKEY_CLASSES_ROOT\PNGFilter.CoPNGFilter] @="CoPNGFilter Class"

[HKEY_CLASSES_ROOT\PNGFilter.CoPNGFilter\CLSID] @="{A3CCEDF7-2DE2-11D0-86F4-00A0C913F750}"

[HKEY_CLASSES_ROOT\PNGFilter.CoPNGFilter.1] @="CoPNGFilter Class"

[HKEY_CLASSES_ROOT\PNGFilter.CoPNGFilter.1\CLSID] @="{A3CCEDF7-2DE2-11D0-86F4-00A0C913F750}"

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