I'm currently creating a software tool that generates images that contain independent RGBA information for each pixel - meaning the red, green, blue and *alpha* components are supposed to be read and treated as separate entities in a single pixel (i.e. no alpha premultiplication or any other data combination tricks).

These images must be stored on disk. The intent is to store them in a way that the various pixels of the image can be easily read, later, by a simple C program, one pixel at a time. Another requirement is that the stored image itself should be visible by at least one OS tool (Preview for MacOS, Paint for Windows, web browsers, or any other commonly-used tools to view images in a computer).

What is the simplest image file format that I could use to store the data as described above? The closest I've found is TIFF; however, the spec requires alpha premultiplication for RGBA values. What other formats do you know that let me store image data in a uncompressed RGBA plain format?

Just to be clear, file size is *not* a concern. The order of the components in the pixel is also not a concern; BGRA is as equally valid as RGBA for all practical purposes in this project.