This is a little excurse in how to get a nicer color into your gameboy camera pictures.
The original pictures have a fixed 4 color greyscale palette. For example black, dark grey, light grey and white (or in values: #000000 #555555 #AAAAAA and #FFFFFF).

To make this more eye friendly, you can use any paint program to alter the colors. Very easy to use is the online pixel editor of lospec. ( https://lospec.com/pixel-editor/app )
They even offer some pretested Gameboy palettes. ( https://lospec.com/palette-list/tag/gameboy )

The more elegant way is to change all pictures with one line of code.
I suggest you first find a palette that does not hurt your eyes.

Now we need a translation table in the format

#000000 #060329
#555555 #8D25DF
#AAAAAA #EC93C9
#FFFFFF #F2FFB0

#inputcolor #outputcolor - for all 4 colors (use a color picking tool or see the instructions below if you are very lazy...)

Save this table to a file called mapped.txt

Now you can use the excellent script called 'mapcolors' http://www.fmwconcepts.com/imagemagick/ ... /index.php

./mapcolors -m -f mapped.txt original.png colorized.png

This produces a colorful picture out of any original greyscaled gameboy picture... tadaaaaa

As I am not happy with the manual solution, I use the command line to obtain the color values and write the table...:

1. Extract the colors of a picture with one line of imagemagicks 'convert' tool:

convert colorized.png -unique-colors -scale 1000% palette.png

This outputs a little 'palette.png' just containing the 4 colors.

2. The used colors in your palette can be cut out by

identify -verbose palette.png |grep 100 | cut -d " "  -f7 |cut -c -7 |sort

Do this for the original picture and the eyefriendly picture. Now we have four original color values (#000000 #555555 #AAAAAA and #FFFFFF ) that have to be changed to the new ones in our examlpe above ( #060329 #8D25DF #EC93C9 #F2FFB0 )

3. Save both, the original and the new color map into files and merge them.

paste -d\  original.txt neu.txt >mapped.txt

4. And here is the final solution: extract the colors and create the table all you need are the original.png and colorized.png :

convert original.png -unique-colors -scale 1000% originalpalette.png
convert colorized.png -unique-colors -scale 1000% palette.png
identify -verbose originalpalette.png |grep 100 | cut -d " "  -f7 |cut -c -7 |sort >original.txt
identify -verbose palette.png |grep 100 | cut -d " "  -f7 |cut -c -7 |sort >neu.txt
paste -d\  original.txt neu.txt >mapped.txt

The new file is the Translation Table

I've spend too much time on this :D