Apple Event: May 7th at 7 am PT
I have been using Macs for many decades, but the recent Mohave macOS seems to cause problems with creating icons. I used to copy an image, and paste it into the icon part of the information window, but the added icons looked blurred. Never had that problem before Mo
have.
Mac Pro
Problem started in High Sierra and was never addressed. In Mojave the problem is slightly different.
In order to get them displayed clearly make sure the icons/ images you want to paste are in a square format and dimensions should be 512x512 pixels or 1024x1024 pixels. you can use Preview to resize. Not ideal when it was so easy in previous OS's.
Don't bet on Apple changing it though.
This article, Create custom icons for files or folders on Mac - Apple Support clearly titled for macOS Mojave, does not even mention that icons/ images need to be of certain sizes or dimensions, so the problem has not filtered through to the support team.
If you think it might actually make a difference try this, Feedback - macOS - Apple
I have no data or prof, but just a theory and it looks like the GPU processing is negatily impacted in Mojave somehow.
Many initially unrelated issues are coming together and all have to do with Intel GPU processing and the Metal API, and since Apple gave up on Open GL.
Why do icons made in Mohave macOS all look blurred? It worked fine until Apple "improved things"
