Do not know your Gimp version ? It shows in Help -> About
Using Win 11? As far as I know you can restore the old mspaint see: https://jamesmccaffreyblog.com/2024/10/1...-11-paint/
Using Gimp 3.2.4 and Win11 (VM) Much depends on your printer settings and only you know those.
Keeping it short, in the print dialogue you need to get the same pixels-per-inch (ppi) value as the image.
(1) Shows an image exactly USletter size @ 300 ppi and that is 2550 x 3300 pix
My printer imposes margins and scales the image down to a resolution of 324 ppi about 90 % of original.
(2) You need to crop the original (trial-and-error) until the image fits. X and Y printing resolutions 300 ppi same as the cropped image.
Once you know the minimum amount to crop you can set up a template and use that for new work.
Using Win 11? As far as I know you can restore the old mspaint see: https://jamesmccaffreyblog.com/2024/10/1...-11-paint/
Using Gimp 3.2.4 and Win11 (VM) Much depends on your printer settings and only you know those.
Keeping it short, in the print dialogue you need to get the same pixels-per-inch (ppi) value as the image.
(1) Shows an image exactly USletter size @ 300 ppi and that is 2550 x 3300 pix
My printer imposes margins and scales the image down to a resolution of 324 ppi about 90 % of original.
(2) You need to crop the original (trial-and-error) until the image fits. X and Y printing resolutions 300 ppi same as the cropped image.
Once you know the minimum amount to crop you can set up a template and use that for new work.