How do I remove the bar across the image of tiled background

Hi !

I'm trying to make an infinity background with bullet behavor.

But when I double width of the tiled background a bar appears across the image.

Check it out :

Check your graphic in a graphics program. It's usually caused by the fact the graphic does not completely cover the canvas area and just stretch it slightly to cover the whole canvas.

I recently had a problem with a tileable fog I made in gimp at 1024x1024. Theres no need for HD fog, so I scaled it down after importing it. It took me a couple of tries to realize that the odd bar wasn't coming from the spritesheet, it was coming from the scaling that was used. I went back and scaled it down in GIMP and it was fine.