Good suggestion! In case you don’t already know how to duplicate an observation, here’s a helpful link: https://www.inaturalist.org/posts/28325-tech-tip-tuesday-duplicating-observations
Afterwards, don’t forget to delete the current spider observation (or combine the 2 spider observations into 1: here is a tutorial which tells you how to combine them: https://forum.inaturalist.org/t/how-to-turn-multiple-observations-into-a-single-observation/9838).
As far as your comment …
… remember that it is not considered a duplicate observation if the same exact photo has 2 organisms, and is used for 1 observation/ID of each. So the spider photos can be on both your spider and your liverwort observations (assuming same day and location as your current liverwort photos).
And as @ahospers already mentioned, click the i on the spider photo after duplication is complete, to see that the photo data is now connected.