Posting photos in classifieds

Hi,
I am probably missing something and I am not the most computer savvy person, alright I am not savvy at all, but I am having trouble posting in classifieds as far as photos go.
Everything is great until I go to put a photo in. I hit browse which takes me to photos on my computer. When I post there are no photos. I suspect the file size is to large. I then put out them on an outside site, in this case imageshack thumbnail size. When I tried to post the URL it went straight back to the earlier problem. Is there a preview for classifieds? I hate to post before I can see what it looks like. I did it earlier today and then deleted the ad because I want people to see what I am trying to sell.
Thanks in advance for any and all help.
Kurt

I don't think there's a preview for the ads, and there is a file limit, I believe may be 2MB, but not quite sure. There also may be a smaller limit than the 2MB that I seem to remember.
I think if you resize the picture to something around 600px X 600px and upload that it should work fine.
As far as I know you cannot upload from URL, just from your local harddrive.
May be the next iteration of the classifieds software will be better.