I need help on submitting my spring trashpick etc, in the spring competition. But when I've submitted it in the correct category, it says "Invalid file- please only submit '.png' or '.gif' and make sure the file size is less than 30kb". Well it is in .png file and less than 30kb. Help :3.
Index it, make sure the file is actually a png or gif. You can do this by hitting "save as", make sure it is the correct file format and save it. Reduce some colours, too.
Can you post the file?