Someone Please Help Me Understand Why Is the Gimp Image Size Bigger

[P1at1n1um]

GIMP Version: 2.10.22
Operating System: Windows
GIMP Experience: New User

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I Created a Monochrome Bitmap image 3x3 pixel on GIMP, I also created the same 3x3 pixel image on MSpaint aswell, same monochrome bitmap as gimp. but the gimp one is 46% Bigger than the mspaint one. why is it occuring?, and also is there any way for me to reduce the size?

example below

[rich2005]

When you come to export the Gimp bmp image, open the Compatibility Options and tick the "Do not write colorspace information" button. That is your extra size.

bmp-options.jpg (35.24 KiB) Viewed 3202 times

[P1at1n1um]

When you come to export the Gimp bmp image, open the Compatibility Options and tick the "Do not write colorspace information" button. That is your extra size.

bmp-options.jpg

Hi, thank you. the compatibility option is not poping up for me when is in mode"image/mode/indexed/use black and white 1 bit pallete"

does it work for you?

[rich2005]

You only get that dialogue with a RGB image.

Just a comment about your test.
You are using a 3 x 3 pix image, so any 'overhead' such as colour space info or a color-map for an indexed version will be very noticeable. That overhead is not as noticeable on a larger images, and usually makes an indexed image file size, smaller than a RGB image.
A comparison: The Win Paint & Gimp (no info) images = 90 B
Gimp (with colorspace info) = 174 B
Gimp 2.10 indexed = 158 B This was broken in Gimp 2.10.22 and fixed for Gimp 2.10.24 however a Gimp 2.8 smaller at 142 B, so something changed for the worse.

You using Gimp 2.10.22 ? Do you get an Unrecognised or invalid BMP compression format. error ?
You need to update to Gimp 2.10.24 see: https://gitlab.gnome.org/GNOME/gimp/-/issues/6114

[P1at1n1um]

You only get that dialogue with a RGB image.

Just a comment about your test.
You are using a 3 x 3 pix image, so any 'overhead' such as colour space info or a color-map for an indexed version will be very noticeable. That overhead is not as noticeable on a larger images, and usually makes an indexed image file size, smaller than a RGB image.
A comparison: The Win Paint & Gimp (no info) images = 90 B
Gimp (with colorspace info) = 174 B
Gimp 2.10 indexed = 158 B This was broken in Gimp 2.10.22 and fixed for Gimp 2.10.24 however a Gimp 2.8 smaller at 142 B, so something changed for the worse.

You using Gimp 2.10.22 ? Do you get an Unrecognised or invalid BMP compression format. error ?

Got it, Went ahead and updated to the newest version. is there any way i can do the 1bit color monochrome bmp and remove the whitespace so as it acts like MSpaint version?