The information provided in this guide is intended solely for educational purposes. This guide is not intended to infringe upon the rights of the original authors or to diminish their work in any way.
You got yourself a awesome set of images and you want to train a Lora, but every image has a watermark of the original author. Clearly this presents a problem since it'll take that watermark and include that in the training. There's two things you can do at this point; you can crop the watermark out of the image or you can preserve the original and remove the watermark using free tools. We'll be looking at the second. I don't have, or want to use photoshop (due to them basically telling me I can't cancel anything until I accept their new terms, which I won't) so we'll be going for the free alternative named GIMP. GNU Image Manipulation Software (GIMP) is still being used, believe it or not, and you can set it up to quickly and easily remove watermarks with these simple tricks!
Prerequisites
Install GIMP (https://www.gimp.org/downloads/)
There's a patch called PhotoGimp that makes it handle more like Photoshop. Available here: https://github.com/Diolinux/PhotoGIMP
Install the Resynthesizer plugin
Windows users can download it from: https://github.com/bootchk/resynthesizer
Linux users can install it via package managers
Copy the contents of the .zip into your plugin folder (If you're not sure where to put it, check Edit > Preferences > Folders > Plugins)
Restart Gimp
Steps to Remove Watermarks
Step 1: Open the Image
Launch GIMP.
Click File > Open and select the image containing the watermark.
Step 2: Select the Watermark Area
Use the Free Select Tool (Lasso) or Rectangle Select Tool to carefully outline the watermark.
Ensure the selection includes a slight margin around the watermark for better blending.
Step 3: Apply Resynthesizer
Navigate to Filters > Enhance > Heal Selection.
In the dialog box, adjust the settings as follows:
Context Sampling Width: 20-40 (adjust as needed for better results)
Sample from: All around
Filling order: Random
Click OK to apply the effect.
And bam! It's gone! The results will never be perfect, because you'll be basically redrawing the image, but this is a simple, quick way to remove a watermark with the rest of the image remaining decently coherent!
If the result looks imperfect, undo (Ctrl+Z) and try adjusting the selection or settings.
Use the Clone Tool to manually refine any remaining artifacts.
The Smudge Tool can help blend the edges more naturally.