Greetings. I am far from the fastest, but I’ve done 30 images in around 18 seconds. I use a memory palace, and I put two images on each locus. I quickly make a little interaction between the two images. For example, if the first image is a rock and the second image is a man holding an umbrella, I’ll imagine the rock crashing down into the umbrella. Nothing fancy or involved, just a quick interaction. Obviously, some interactions are easier to imagine than others, but it all gets better with practice. The last four images I just grab verbally to myself, e.g. “Rock, Baby, Dog, Clouds”. Once the recall starts I quickly put those four into place so I can forget them and get back to putting the other 26 in the right order.
I have five memory palaces with 15 loci each that I use for practicing images, and I rotate through them. Just do it over and over again and you’ll get better doing this.