I've noticed that Osu!'s sprite rendering engine tends to have weird artifacts with certain images. Most notably, I've had to work around white borders when I use the stroke layer effect in Photoshop by using outer glow with a small size instead.
However, I've run into a new artifact that I can't seem to work around. On the scorebar (scorebar-colour@2x.png), I'm using gradient overlay and inner glow on a simple rectangle. However, when I load the sprite in-game, I'm getting a gray line on the left side of the bar that doesn't exist in the source file:

Edit: For some reason the image isn't showing up so here's a direct link: http://puu.sh/hFbwC/af4cd72fda.jpg
Does anyone have any idea what causes this and how I can work around the problem?
Edit2: Found a solution, for some reason Osu! doesn't like hard edges, so adding a small low-opacity border worked.
However, I've run into a new artifact that I can't seem to work around. On the scorebar (scorebar-colour@2x.png), I'm using gradient overlay and inner glow on a simple rectangle. However, when I load the sprite in-game, I'm getting a gray line on the left side of the bar that doesn't exist in the source file:
Edit: For some reason the image isn't showing up so here's a direct link: http://puu.sh/hFbwC/af4cd72fda.jpg
Does anyone have any idea what causes this and how I can work around the problem?
Edit2: Found a solution, for some reason Osu! doesn't like hard edges, so adding a small low-opacity border worked.