That smile looks tantalizingly familiar but I can't quite put a name to her ...
Re making your pictures smaller, try
http://www.tinypic.com. You don't need to register or sign in if you don't want. On the tinypic front page, select the file from your PC that you want to upload, select 'image' from the checklist then select 'resize' and choose the size you want. Thumbnail may be best for your purposes.
Click Upload Now and wait a moment or two (you may be asked to enter a code at this point to prove you're not a robot). When the upload is done, click on View Full Size and see what it looks like. If the size is wrong, then you can go back to the front page and try making it larger or smaller.
Once you're happy with the size, click on the box to the left of the screen labelled 'IMG code for forums & message boards' to highlight the code string shown and Control+C to copy it.
Then you can paste it into your forum message; it will show as a URL but you can check that it works by doing a Preview before you submit.
Sorry, writing all that down sounds horribly complicated but it's quite simple in practice! HTHE