See also tips on making ZIP files for bulk uploading.
Please note that gallery will only accept PNG, JPEG and GIF images - which are about all that might be sensible on the Web anyway. At some point we will let you upload a broader range and convert them, but that is a little way off.
If you're wondering how big you should make your pics, so that people will be able to see them properly at a variety of resolutions, just don't worry about it. Put up the biggest size that you think is sensible for the Web. We scale them down for users who want that, but we'll never be able to add more information than you give us to begin with.
If you find you have uploaded a picture to the wrong gallery, then you can quickly switch it to another gallery for a few hours after uploading. If you are too late then you will have to delete it and upload it again.
If you upload a picture and it is upside-down or on its side, don't worry. Just go to the picture's main page and choose 'Rotate' and you can fix it straight away.
Any pictures you haven't filled in names for are kept in your pending uploads, which is also linked from the front page when you are logged in.