They are so thick it makes it hard to make sure the sprite is properly selected. Compare this:

Left Atlased, right Aseprite.

Thanks!

Do you guys see the pictures? I do see them when I edit the post, but not when seeing it, weird.

Copy paste does not work ok, had to create an image, save it and then upload it here.

Hello. Thanks for the feedback, and that's a good notice and a somewhat known issue, I will see what could be done to address it in some future update.

For now I can suggest you trying out "Options-> Configuration -> Appearance -> Regions Outline" setting, and tuning the Alpha value there to make selection borders semi-transparent. It is not ideal, but it could reduce visual clutter for small sprites.