I added once to my own site as well and the photos were not allowed in my own site. The site is not my own, my subscription is also not mine either evidently even though I paid for it.
mschleisner ...there is specifically a section in a personal site for photographs...especially such things as that fave one of Fido the pet.
If you have a photo/image being rejected even though it is intended for your personal page that will be ONLY because you are attempting to upload it to your [personal] wallpaper gallery...and, as with anyone's wallpapers going anywhere, personal or public they are actually supposed to be wall proportion as well as suitable/passable through the moderation process.
Putting your photographs directly into your photo gallery [read NOT 'wallpaper gallery'] is not moderated. Anything goes [as long as it is not porn/racist/etc]. These images can be any size...any content you wish.
Here is mine....yours would be similarly named....[replacing the 'Jafo' with your nick]
http://jafo.wincustomize.com/photos.aspx
Now....if you look there you will find all sorts of images....even of my cat. Just the place for what you were intending to submit via the wallpaper gallery upload process.

That is hardly going to appeal to anyone as a wall......other than maybe me and my 2 sisters....except the latter are not 'into' computers...so that leaves me...the rug-rat in the pic.
http://mschleisner.wincustomize.com/photos.aspx is most likely your link to the same facility/feature of Wincustomize.com, accessible to all who wish it.
I need to apologise on behalf of any mod who may have appeared to you as 'angry'. My guess is it is more likely to be a touch of 'frustration' towards the recurrence of misplaced submissions.
http://jafo.wincustomize.com/photos.aspx?cmd=addphoto&a=1&type=2
That is my 'add photo' link....it is direct and unmoderated, as is yours....