Optimize PNG images
Online PNG and APNG optimizer/compressor
The PNG optimizer can losslessly compress and reduce PNG image size. It can be used both for standard, single-image PNG images, and for animated PNG (APNG).
For animated PNG (APNG), you can use the "Drop every second frame" option to remove half of the frames. This is a lossy operation that will reduce the frame rate and file size, but keep the animation duration (speed) roughly the same.
It's very advisable to optimize images used in web, as it can save bandwidth and make websites load a little faster.
The actual size reduction percentage may vary depending on what optimizations have been done previously for a particular image, but it can reach more than 40% in some cases, so give it a try.