So this is happening after you dingled or after you installed market?
good question not sure. i did right after another... might be market. cause now that i think. the android has a folder for thumbnails. will have to verify with my bf' epic.
thumb nails of the pics same issue here. and if.you delete the thumbnail ones, the others get erased also. idk why but i hope a work around comes out.
If you are deleting thumbnails folder, it will not delete your original pictures.
Go in application, click on edit and delete thumbnails folder, not every file indivisually and it will not erase your original files.
Thumbnails folder is being created because of android as it does same in adroid phones.