I've actually stopped including screen shots with my skin submission. This is for many reasons, one that has finally being remedied according to Skuzzy.
1. They weren't being used. (again, seems to be finally coming)
2. It's two more files per skin to make, and ensure meets the required name, size, and file type. (not too hard, just more menial work per skin. which when considering the next two reasons makes the entire process easier for me, especially when I use a far larger size of preview image when I post a preview thread on the BBS. so in effect, I have 3 versions of the same screen shot.)
3. if there is a single mistake with a single file, I must resubmit the skin by uploading every file again after correcting the single flaw on my end. (it would be nice to be able to make adjust the single file that's holding up the process, instead of starting from scratch on the submission page.)
4. The submission page has a ridiculously short window to upload all the files before the page times out (under 5 min). I have to prepare all the skin info for the text box or else I risk taking too much time typing it fresh and having to start from scratch due to timing out.
Seriously Skuzzy, as far as all of us skinners are concerned, I think we'd rather you focus on giving us the ability to update the existing skins over providing preview screenshots and thumbnails for new ones.
I hope the hangar in the new version allows for a better viewing angle for the aircraft and the ability to move the camera to view the skins. Picture preview on the website is small potatoes, compared to having an easier time seeing skins in the hangar.