Why is the file size so large when saving in Sketch?

Question

User interface

I noticed that when there are a lot of pictures in the design, the Sketch file size becomes very large, it seems that full-size duplicates of pictures are saved somewhere, because. even when I reduce them, the file size does not decrease. How to solve this problem?

Answer 1

Try to compress the source like this: take.ms/hYylV

Answer 2

Obviously, the images are not linked, but "sewn" into a file for further work.

Answer 3

Alternatively, if you are sure that a larger image size is not needed, select the image and:
Menu / Layer / Flatten Selection to bitmap
Also in the settings there is an item Flatten Bitmaps: 1x or 2x