Question

what is the default image size in gimp?

Answer 1

the width of GIMP 's default image size, which is 256 pixels.
;-)

Answer 2

Notice that the Scale Image menu item contains three dots, which is a hint that a dialog will be opened. If you have a desired width, put it in the dialog at the top where it says Width. If you don't have such a number in mind, you can steal the width of GIMP 's default image size, which is 256 pixels.

i hope it help u..