IPA: /ˈfoʊtəʊˌfɪnɪʃɪŋ/
KK: /ˈfoʊtoʊˌfɪnɪʃɪŋ/
The process of developing film and printing photographs from it for customers.
After taking pictures on vacation, I took my film to a local shop for photofinishing.
Photofinishing → It is formed from "photo-" (from Greek "phōtos", meaning light) and "finishing" (from Old French "finir", meaning to finish). The word refers to the process of completing or developing photographs using light.
Think of 'light' ('photo-') being used to 'finish' a photograph — that's how photofinishing works.
No commonly confused words.