I'm sure I'm missing something really obvious 
here. I went to post an image in a recent "show 
me" thread and had no luck at all. Created my 
image, checked its size at 32kb. Logged in, wrote 
the message and clicked the browse button, 
selected the image from my hard drive and made 
sure it was the right one in the box after I'd 
done so, then clicked the post button... and 
nothing appeared except my text.

It's obviously working so it must be something 
stupid I'm doing ;)