The thread just below this one,
How to make a bigger signature?? brought up an interesting point. I was going to update my signature to add Chico. My signature pictures are hosted at Photobucket, but their servers have been a bit flaky lately. I decided to upload the pics to ParrotChatter's server instead. Here's where it gets interesting.
When I did that, and previewed my signature, the photos had shrunk in size, by about half! I changed the links back to the photobucket server, and the pics were back to the larger size.
This reminded me that I remember others having issues with signature pic sizes as well, and now I understand why! PC's gallery software is apparently automatically resizing these photos down (without regard for the fact that the originals were already within size guidelines), or for some reason they are displaying differently. It may be possible to size the photos twice as large as you intend and then they might display in the size you expect, but that's a bit counterintuitive. The easy workaround is to use Photobucket or another public photo hosting site, but I'm just curious about why this is happening? I'd just as soon keep all my photos here, really. Makes for less possibility of broken links in the future.