I would like to write a utility to create image thumbnails and attach them as .EAs to the images - ideally a commandline utility that I can start and let it recurse through a series of subdirectories.

That way, when I start PMView, the thumbnails will already be in the File Open dialog, rather than having to create them.

To do this I would like to have more details about how PMView attaches thumbnails to an OS/2 file. I can examine the EAs myself and learn this; I suppose they are little gifs?

First: has such a utility already been written? and

second: if not, are there any "gotchas" that Peter can warn me about before I start?

The thumnails are standard OS/2 icons stored in the .ICON EA of the file.

Storing the thumbnail is easy. The hard part will be for your application to decode the files. Of course if you only care about a few formats, say JPEG and GIF, this is no big deal...

PMview can already do this for you (other than the recusive part, as far as I know). Right click on an empty area in the File Open window and change Thumbnail Type to "Icon Thumbnail". Now, you can select & right click on the images you want to create thumbnails for by clicking "Icon Thumbnail". This thumbnail is then stored in the EA's as a standard icon. You can control whether or not this action is automatic by right clicking in an empty space in the File Open window and looking at the "Icon Thumbnails" submenu.

If you set "Icon Thumbnail" to "mixed" it will use the saved thumbnail from the EA if it exists, otherwise it will create a temporary one on-the-fly.