I hacked together a simple website to create chord charts online (.png and .svg images): https://chordpic.com.
The use case of this website is if you don't want a million features but just want to create some simple charts very quickly. I created this site to replace the website chordpix.com which recently went dead.
It asks you to name the chord (optional, this is shown on the top of the chart), give the starting fret (fret 1 by default), and the number of frets (5 by default).
Then you simply click on the strings to add a finger there. To add a barre chord (basically a finger over multiple strings) you can simply click and hold the mouse button and "drag" to any other string to create a bar reaching over the strings.
This is all explained in detail with animated gifs on the help page at https://chordpic.com/help
ChordPic is not as sophisticated as other tools. It will not figure out the chord or provide you with alternative chords or anything like that. The main goal of this tool is really to simply create a chord chart very easily and however you want it. It will also not prevent you from eg. putting multiple fingers on the same string. Think of it as the Notepad of chord chart editors. Yes, there's also Microsoft Word that offers you spell checking and numerous formatting options. But sometimes you just want to write some text quickly without any fancy features.