This blender addon is GUI for : texture-synthesis
After installing addon go to addon preferences and select directory where texture-synthesis.exe is installed.
Addon panel is located in IMAGE_EDITOR -> Right Sidebar -> Texture Synthesis panel.
And there is trick - if you Shift + click on 'Run texture synthesis' button then all images in folder will be converted to tileable textures (only works with 'Simple generate' synthesis method though)