In Chrome you can press F12, to open the Dev menu.
Then under "Application" you will find several sections.
You have stuff like "Image" and "Media" will appear if you play any video.
If you open this panel and then open the pics, then the pics will appear listed there, you can then open them in another tab to download them. You will get the thumbnails and the small version on the post, but if you open it you'll get the full res version loaded there.
Same for videos, but usually you need to have played a certain amount of them for them to appear in that menu.