pixelmator pro unwieldy file size

Talk about Pixelmator Pro, share tips & tricks, tutorials, and other resources.
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2020-06-07 12:06:47


I have come across the following issue with Pixelmator Pro: yesterday I imported an .JPG file into Pixelmator Pro 1.6.3. Magenta, size 11.2 MB,
After I had saved the image as a Pixelmator Pro file to be worked on, the size of the Pixelmator Pro file was 83.5 MB, before I even worked on it. When I doubled the image for an second layer (I like a spare copy when I work on images), 166,5 MB.

My MacBook AIr with MacOS High Sierra 10.13.6 can't really handle these file sizes, the system slows down and is barely responsive.

How is it that Pixelmator Pro comes up with these unwieldy file sizes. I have used Pixelmator Pro for a few years, and I can't remember having trouble this before. Is this some sort of bug, or is this something I should learn to live with?

Many thanks for your answer
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2020-06-10 15:07:48

In the Pixelmator Pro file format, image layers are saved as compressed image data and image data actually takes up a whole lot of memory, even when compressed as you can't use algorithms that are too aggressive with the compression and therefore slow. Image sizes are much lower because formats like JPEG offers lossy compression and discards data at the cost of quality (not an issue when saving once) while formats like PNG are quite slow when you end up compressing the image a lot. Pixelmator Pro has always worked like this and most image editors do, too, so this isn't too unusual. There are certain optimizations we can make (and plan to do so) but, generally speaking, you'll get similar sizes with most editors.
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2020-06-10 18:51:05

Thanks for the answer!
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2020-06-11 13:38:30

No problem!