[Mediawiki-l] Strange artifacts in thumbnail and preview images

[Sandy Rozhon]

I just scanned and uploaded a batch of images which subsequently went 
into a gallery on my Wiki.  For some reason, the thumbnails and the 
preview images all seem to have something strange happening to them, 
but the full resolution image is just fine.

Does anyone have a suggestion on how to clean these up and why this 
is happening?  I've done similar processing on hundreds of other 
pictures without running into this problem.  I scanned these at 500 
dpi, enhanced the contrast, and adjusted the color balance.  Then I 
used Microsoft's "resizer" toy to bring the file sizes down to a 
reasonable level for uploading.  I scanned at such a high dpi because 
I knew that I was going to ultimately resize these images.

Here's the URL (look for the 1970 Memorial Day Parade pictures):

http://www.zodiacal.com/brooklyn/index.php5?title=St._Barbara_Photo_Al
bum

Sandy