Issues when importing Re-sized Tilesets

I’ve been running into some problems when trying to use tilesets that I’ve resized using an image editor. For example - I’ve downloaded a few tilesets that I want to use in my game, but they are 16x16 and I want them to be 32x32 in my game. So I used an image editor ( to double the dimensions of the image and then import the resized tileset into Tiled with tile width and height of 32x32. What ends up happening is that the borders of the tiles don’t render correctly anymore - instead, the borders often contain pixels from the neighboring tiles. I’ve attached an image to illustrate what is happening when I use the bucket fill tool on a tile that is supposed to be just a solid block of purple.

Could anybody help me out with this issue? Because the game framework that I’m using doesn’t currently support scaling of tilesets, I believe that I have no choice but to resize the tileset to be 32x32, but I can’t seem to get it to work with any of the free 16x16 tilesets that I’ve downloaded.

edit: fixed title of post

Nevermind - I just fixed the problem by using a different image editor to resize the image ( I believe it worked with Gimp because Gimp’s scaling feature allows you to turn off interpolation.

Yes. If you scale pixel art you need to be careful that the editor does not do any kind of interpolation and make sure to scale by a integer value to allow to keep sharp edges.