A simple tool for baking a bunch of images into one larger image. Will write a sprite atlas and a json file that tells you where the sub images are.
spritebaker -width 512 -height 512 -input [image1.png image1.png ...] -output sprite_atlas.png
Required
-width Output image width.
-height Output image height.
-input A list of input images that will be packed into the output image.
-output The output image file name.
Optional
-bg_color Red, green, blue, alpha channel color values for the background. Range 0 - 255.
-padding Padding around each sub image in pixels.
-trim_images Trim fully transparent pixels in the input images.
-sprite_format Output special sprite format.
Here's two outputs from the tool. The first one is 650 x 650 without trimming and the second one is 512 x 512 with trimming.
This tools is build using nothings stb libraries, image reader/writer library as well as the rect packing library. For reading and writing json files nlohmann's json library is used.

