[retroplayer]

I have not played with Steganography myself a whole lot, so IDK if it works well with .exe files, but here are a bunch of tools that allow you to hide files inside of images: https://www.geekdashboard.com/best-steganography-tools/

Like I said, I don't play with steganography much, so your mileage may vary. I haven't actually used these tools. The way my professor told me it works, is by changing the least significant bit in each byte of the photo. The photo changes very slightly, but not enough for anyone to see. That being said, if the file is big enough, you might start to see differences in the photo, so be wary.