Don’t know about Jerboa, but Connect for Lemmy has a feature that you can type in keywords you want to use as filters, and posts with those words in the title are automatically hidden.

I use it to filter out political posts, and after using it in this way my Lemmy experience has drastically improved. You may be able to use it in a similar way for spider related stuff, maybe Jerboa can add a similar feature.

As far as images without anything to note its a spider in the title, you’d need to add image recognition, which is something more likely to be added to Lemmys backend than as a clientside thing.