Anastasia - if you go to the gallery it's quite easy to upload photos from your computer.
File size limit is 150kb.
Click on "Gallery" near the top right hand corner of the page (does top right hand still work when we're from downunder!

)
There's a prompt to "upload pictures", so click on that. It'll take tou to another screen where you can select the album you want from a drop-down menu.
Select A2K members pets
Then there's a place to click "browse". do that, and that takes you to your computer - so go and pick on the picture you want to upload. (Remember 150kb - so check file size first)
Double click on that, and it should bring it up in the box - add any information you want, e.g., name, comments, then click "Upload picture".
A moderator has to approve the pics, so they won't appear immediately - but just wait a day or so and they'll be there!
Good luck!