Programme for generating nice text effects by command line

I'm searching for a programme that create images with various text effects by command line. That effects can result in static images (like [login to view URL]) or GIF animations (like [login to view URL]). So I give the programme the text, other parameters etc. and it creates the GIF file which also has a optimized file size. So in other words I'm looking for the backend of such websites as the following: [login to view URL] [login to view URL] [login to view URL] (<<<-- this one is VERY COOL) [login to view URL] [login to view URL] [login to view URL] -> I do not need a full clone of the whole portal, I'm only interesed in the backend programme! -> Please look at the attached images for examples of what the programme should able to produce. -> It should run on a Linux server but if a Windows server is needed this would be no problem. I prefer Linux, but in the end this doesn't matter. -> Instead of a single command line programme some kind of daemon would be possible too of course. -> I really don't have an idea of which size this project is. I've chosen "medium project ($300-1500)" here but please feel free to bid whatever you think. Maybe there does exist a solution already that could be licensed, I don't know and hope you can help me!