I finally posted one picture but it is really too small. I have seen people posting bigger pictures.

That's because you posted it as a bitmap (bmp) image...
bitmaps are uncompressed, meaning each bit in the picture represents a pixel (thus the name bit map). JPG (jpeg) images are compressed images - they lose some quality but usually not enough to notice (as long as you don't use a cruddy program like Windows Paint). For a bitmap to be 1 pixel (1x1), 24 bits is needed. For it to be 800x600 (480,000 pixels), 11,520,000 bits (about 1.4MB) is needed! For an 800x600 jpeg size may vary but is usually well under 70KB (0.07MB). The limits of a 66560 byte post attachment roughly equals a bitmap with a square size of 148x148 - rather tiny!

Use a free program (like this one for windows ) to change the image from bmp (windows/OS2 bitmap) to jpg (jpeg compatible).

EDIT: I see David Speed linked to Irfran View. It's a very good program and should allow you to convert a bmp to a jpg if I'm correct.

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2021 Charger Scat Pack Widebody "Sinabee"
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