Sure, the omarchy boot logo looks nice, but you want to make it your own. Check out the steps below to rice it:

Locate the image

Replace the image at /usr/share/plymouth/themes/omarchy/logo.png.

Note: You might need to use sudo to copy the file to the directory.

Format your image

Install magick if you do not have it yet: sudo pacman -S imagemagick

Use the following command to set the correct attributes for your image. Replace $INPUT_FILE with your image filename.

magick "$INPUT_FILE" \
  -density "72" \
  -units PixelsPerInch \
  -depth 8 \
  -colorspace sRGB \
  -type PaletteAlpha \
  "logo.png"

Optionally, if you want to might want to make the background transparent using

magick "$INPUT_FILE" -fuzz 15% -transparent black -trim +repage $INPUT_FILE"

Run the command

sudo limine-update

Restart your computer to see the changes.