Sounds like your picture is too big, you have 304,182 bytes and the limit of the board file upload is 250,000 bytes per image. You should make sure that you are using the .jpg format as this uses the smallest amount of bytes and is the easiest for everyone to read. If you are using .bmp it is easy to exceed the limit as this is the largest file format for images. Also try cropping the image, eliminating blank margins, etc. This is easy to do in any image editor, especially MS Paint. Keep trying and good luck!