The first attachment is the one that shows up as the thumbnail. To change it you have to upload all of your photos again with the one you want as your thumbnail as the first upload.

Glad to help!

Hi
Just wanted to say thank you fit the amazing idea on your prime armor mod using defense red alert , I'm very excited to try this idea so I just wanted to let you know that I will fully give you credit for it. Planning on working a unusual character lets see how it turns out but anyways once again I want to say thank you for sharing the original idea and most of all for the inspiration. :)

Take care