With 2020.2, the icons are stored in database. But when you would reuse an icon already used in your project, you have to select it again as image upload, so the icons are stored multiple times.
Would be better if there is a central repository (per project / version) where the icons can be maintained and where you can refer to.
An example is the info icon, what can be used on multiple subjects.
See also
I run into the same problem.
It would help a lot if I had the option to download an icon in the 'Icons' table, instead of, what happens now, opening the icon as an image in MS Paint.
Would like something similar for used colors and fonts.
From 2022.2, the Icon repository is fully implemented!
No longer you'll need to download and reupload previously used icons. Simply select an icon from the repository and link it to the object.
And yes@Harm Horstman , we made sure to include a Download button 
*We do advise to read the Release notes when they come available as this new repository causes your dynamic model procedures to fail if they use the icon and icon_data fields in table objects.