This is an example of basic gallery functionality with quite concise code. Click a thumbnail to view the full size image, and click the full size image to restore it to a thumbnail.
The images are screenshots of images generated by @ErraticSelection's project "Seed to Noise interpolator": https://scratch.mit.edu/projects/784589893 The number in the lower left is the seed number, which can be input in the original project to generate the same image.
