Can't see PNG previews in Windows 7?

Solution 1:

I had this same problem and was able to fix it with two steps, although, I'm uncertain I actually needed to do the first step:

1. In Windows Explorer, I right clicked on a .PNG file, went to Open With, selected Choose Default Program... and chose Windows Photo Viewer as the default program to open .PNG files. This changed all my .PNG thumbnails to an icon of flowers. (I don't think this was required, but including what I did for completeness.)

   (If the menu is not visible press Alt)

2. In Windows Explorer, I clicked Tools, Folder options, went to the View tab, expanded Files and Folders and removed the check mark from Always show icons, never thumbnails. (I think this is all I had to do to make it work, but have not verified that.)

Solution 2:

It could potentially be an issue with the icon cache on the computer.

Perhaps take a look at this issue here I don't know if its the same issue but it seems to be a few easy steps that could potentially resolve your problem

Rebuilding the Icon Cache Database

1. Close all folder windows that are currently open.
2. Launch Task Manager using the CTRL+SHIFT+ESC key sequence, or by running taskmgr.exe.
3. In the Process tab, right-click on the Explorer.exe process and select End Process.
4. Click the End process button when asked for confirmation.
5. From the File menu of Task Manager, select New Task (Run…)
6. Type CMD.EXE, and click OK
7. In the Command Prompt window, type the commands one by one and press ENTER after each command: CD /d %userprofile%\AppData\Local DEL IconCache.db /a EXIT
8. In Task Manager, click File, select New Task (Run…)
9. Type EXPLORER.EXE, and click OK.

Solution 3:

By following the next two steps, I was able to have the .PNG thumbnails restored. I am not sure whether both of them are necessary to fix the problem, though.

1. For me, the problem was caused by installing another piece of software (SageThumbs, in my case), which allowed me to display thumbnails for graphic file extensions that Windows 7 doesn't support natively. By turning off the function to generate thumbnails inside this third-party software, the cause of the problem was - presumably - gone.

2. Get rid of the current set of cached thumbnails (in '%userprofile%\AppData\Local\Microsoft\Windows\Explorer'). Trying to delete them manually didn't work, nor did selecting the option in CCleaner ('0 bytes removed' message). I was however able to delete the Windows 7 thumbnail cache by going to Start/Accessories/System Tools/Disk Cleanup, and selecting the option in the options list.