Windows Thumbnails won't appear?, Part 2

Yesterday, I wrote about a problem that Ed B. from Long Island, New York had with some pictures not showing up as "thumbnails" in Windows XP. I suggested that Ed may have inadvertently saved some of his graphic files with the wrong extension.

I received a few suggestions from readers with their thoughts. In fact, Pippie wrote to tell me about a security issue with viewing thumbnails in Windows XP:

" MS turned off a few features in the Thumbnail View for stability & performance reasons, starting with XP Service Pack 1 release. They took away the functionality to view HTML files in thumbnail view as well as most Web content files. The following file types have been disabled from thumbnail view: HTML documents (.htm & .html files), XML documents (.xml files), Internet email messages (.eml files), & Internet news messages (.nws files). "

Rick from Portland asks:

" I wonder if he can open the files in his image editor? It could be the files got corrupted and just aren't in the proper format to be seen in preview or an editor regardless of the extension. "

Robert P. is a Systems / Internet Operation advisor for Badger Office City, and suggested that there might be a problem with how files are saved under Windows XP:

" I too have this same problem.

I also save many images off of the Web and have never had a problem except under Windows XP Pro. For some reason the file is saved as "a file" with no extension. When I go to save the image, it shows in the dropdown as the GIF, JPEG, etc., but when it saves it just saves as a 'File'. When I look at the file properties, it just tells me that it is a 'File'!"

Side note: I rip graphics from Google all the time using Windows XP, IE 6 + Service Pack 1... plus all the latest bug fixes, but haven't experienced this problem yet.

Teresa B. says that Irfanview (a free graphic viewing program) tells her if she's accidentally saved a graphic file with the wrong extension:

" Irfanview is a wonderful free program and I always try to keep it updated to the latest releases. In fact I have made Irfanview my default program to open and preview all of my picture files."

Michael M. also recommended Irfanview and speaks of a problem with Internet Explorer:

" Viewing JPEG2000 format (*.jp2, *.jpc, *.j2k) images with Internet Explorer 5+ is fine, but saving these image types is another story. In my experience, IE saves it with the wrong *.jpg extension. This is why Windows Explorer isn't able to create a preview thumb for it. Use IrfanView and it will ask you to rename or save the image under the proper format. "

Mike. O, a network administrator, suggests that there is a preview file size limit:

" There is an upper file size limitation on how the preview feature works. Although, I'm not sure exactly where the threshold is. Some files (regardless of the type) will never display a preview image if they're over the size limit. "

Mak A. suggests that the thumbnails.db is corrupt:

" I believe the thumbs.db file holds the thumbnails previews. Delete it to generate a new one. "

Side note: I checked to make sure that this is OK. PC World Magazine suggested that deleting the thumbs.db file will not pose a problem. Just make sure that the file you're deleting isn't another thumbs.db file from another program that uses the same file name.

In addition to my suggestion yesterday, these are all very plausible suggestions sent in by readers. Some suggestions are new to me, so I can't verify their validity -- only that the suggestions appear credible.