When you press F10 and take a screen shot it saves as bmp. Bmp files are not allowed to be uploaded in the forums. How do I convert the file or save as something different? I have quite a few images from exploring and wish to start showing some.
there are a number of websites that will do the conversion for you but the ones i've seen are limited to the file size you can upload.
the best solution is to use a program such as the gimp (or even MS paint) to do the conversion for you, you can get the gimp free from here: http://www.gimp.org/
I think the easiest thing to do is to just upload it to imgur, it will convert the bmp into jpeg or png automagically. If you have slow internet, it's best to convert before uploading. But imgur is still nice because it's got album functionality where you can add titles, captions and even do basic editing such as cropping.
I've always been partial to XnView; it's probably not as intuitive as others but allows for batch processing beyond conversion. (Ex: cropping, scaling, and format conversion in one batch)