Pictures are drawing commands executed by Drawing, not bitmaps. The pen starts at X=127 and Y=63 (Y counts up from the bottom, so this is screen row 112). 0 ends the picture. 8 and the next two bytes move the pen, with bit 7 of X set. Bit 7 draws a line: bits 0-2 are the direction and the next byte holds the step in its top bits and the length in its low six bits. Bit 6 fills in the ink from bits 0-2, using the next two bytes as X and Y. Bit 5 paints attributes: bits 0-2 are shifted up to the paper colour, the next two bytes form the attribute address with 16 added to the low byte, and each following byte is a run until 255. Bits 0-1 of a run select up, right, down or left.