Hello 415east
personally I bought the middel one, just because the entry model only has 2 USB ports and I have a lot of peripherals to connect (external HDD, CD burner, TimeMachine HD, printer etc. ).
Honestly, I'm coming from a Mid 2012 iMac with 16 GB Ram + SSD and I'm not satisfyed by the new iMac M1.
For sure graphical performance (3D, rendering etc.) are better than the old one, but my ovrall experience is worst.
Mailnly with the new M1 processor most of the Softwares are no longer working, than I have big issues with Photo App (I used a lot with the old iMac).
If you also do video editing, consider that FireWire is no longer available at all and you cannot connect DV devices, this is another negative side (considering my use of it)
Anyway, excluding my personal experience, I think the middle model is enough for Photo / Video editing (also considering the price)