Tilemaps have background color - how to make transparent

Hi - if you look at the Kenney tilemaps / sprites kenney.nl/assets/platformer-art-deluxe they have a blue color as the background -

When I am creating a game, is there a way to make the entire blue background transparent WITHOUT bringing it into an external editing program and selecting it and deleting it?

There are areas inside of elements that require manual selection also, and this could get tedious. I thought the Kenney assets were already transparent? It is a PNG.

Is it something to do with an alpha channel? Thanks! :)

Not all assets that you download from the internet can be used out-of-the-box, many will require some modifications.

Kenney's archive has each tile saved in separate files.

You can use Gimp or a similar software to create a grid and assemble your entire tilemap from the individual tiles.

lg2d

Please go back into the folders and look again. The only images with blue backgrounds are the ones labeled as "preview" and "sample" pngs. Those are not sprite sheets. The ones you want are labeled as sheet.png and spritesheet.png (or similar). They do have transparent backgrounds.

When you visit this page: kenney.nl/assets/platformer-art-pixel-redux and download spritesheet.png it has a blue background!