Stego 8 mission is really easy actually.
After you download the picture zoom in.(i zoomed 1000% using photoshop). You notice that there is a bar composed of squares.Each square is somekind of red. First thing that i taught of doing was to screw around with the rgb values but thats a dead end.
Use the eyedrop tool to pick up each square's color. You will now notice that each color has in composition only red.
At this point you might want to write down each red value.
First box has red value : 112 and so on
Then convert each of those to hex: First box rgb is 112,0,0 -> converted to hex is 70 00 00 I have split the hex composition so you can see that 112 in hex is 70
Do this for each square and note the values down.
Look up for each values in here http://www.asciitable.com/
hex 70 would be "p"(without the quotes xD) in ascii.
OR even simpler... 1) load file into hex editor 2) examine HEX values for some thing very obvious (roughly 50% the way through the file) 3) job done