Feature Request: Image Label/Watermark

[zombiepigdragon]

It would be helpful to be able to add some text to the image in a corner to identify the project name/version. For example, I'm using this utility (technically, the version from #11) to render packages (i.e. linux-lts) that I have installed as a wallpaper, and I would like to add either a watermark or a block of text that identifies what it is. I don't know what appropriate cli arguments for this would look like or exactly how it would best be specified, but I spent a few seconds in GIMP to simulate the idea: Throwing out ideas, the cli (building off of #11's cli) could add a heading for "LABEL" with the following options:

• --label: Text to include in the label
• --label-relative-to: One of "top-left", "top-right", "bottom-left", "bottom-right"
• --label-size: Percent of the image for the label to take up vertically (example 10)
• --label-color: Color of the label in hex RGBA format
• --label-font: Font used for the label I would be happy to implement this myself after a cli lands in this repo, if you aren't interested in doing it yourself. Thank you for this interesting project!