here's the code, you can see that i commented out a (untested, copy & pasted) rng, you can make the generator generate a random pattern-based image, but the "default" is to get the user input and then store it in a 32bpp bitmap.
https://pastebin.com/rV6msppB

To avoid links going stale you can also post the code directly to this board either as an attachment, or as inline text when it isn't too long.

yeah, i know, i do that 'cos i'm used to send code via pastebin lol

It is working but I cannot understand the content of this 8x8 bitmap.
EDIT: "a random pattern-based image", ah, now I see what it is.

For example, my screenshot shows a 2000% magnified bmpgen.bmp.

it's simple, the characters you type are bytes, and then these bytes fill the variable conten, and then this variable fills the bmp file starting at offset $7a, turning the bytes into colors. each 4 bytes is actually a pixel, so if you type "abcd", then you'll get $61,$62,$63,$64, which turns into gray on bitmap.