Say image A is a static portrait drawing of someone. You'd like to make an animation that has no movement of the artwork, but just alternating re-colorations of the portrait in such a way that it changes the hue of the image with the same smoothness of pulling the Hue slider in an image editor back and forth between, say, red and blue.
Which free software will allow this to be done, ideally without having to lay out each frame between red and blue, one-by-one, as a .gif so maybe .mp4 even?
Any non-linear video editor will do. There are several free. Try the first one. Is very lightweight.
This next one has a little weird sub-directory system, but it is reasonably lightweight too.
From here, they are overkill for what you need but will get the job done.
Hit Film Express (When downloading move the Price slider to the left)
Simply put one image on one channel and another on a second channel and choose the fade-in or fade-out tool as needed.
Here is a capture from the first option.
One image over the other and right click
There are several ways to do that in each application, so you might need to look at the documentation or google a tutorial.
One image over the other on the same channel
This will not animate the hue slider. You need to manually prepare the different keyframes or images for the transitions.
You can also do this on PowerPoint with the dissolve transition between slides.
For the real deal
Use Blender. It is pretty complicated because you need to configure a ton of things. But the basic setup is this:
The red circles are places where you need to pay attention for your specific question.
