ItsLitho
ItsLitho is an online lithophane generator, similar to 3DP Rocks (opens in a new tab) but with more advanced features.
Using this tool, anyone can convert 2D images into 3D lithophane reliefs that can then be printed.
The basics are simple to understand, and does not require an account.
This is the default homepage for ItsLitho. Head to the Upload button first to get your image onto the tool
Once you have uploaded your image, go back onto the Model tab to see how your lithophane might look.
There are many options and changes you can make here like changing the size, thickness, and shape of your lithophane. Try changing the shape using the dropdown option into something like a sphere.
Each shape will have its own set of options and settings. Work your way through all the different options until you end up with something that you are happy with.
When you have finished, click on the Download button and select "Lithophane + Attributes" to download an STL file.
This file can now be 3D printed using a tool like Cura (opens in a new tab), or edited and extended further using something like Meshmixer (opens in a new tab).