Google Sheets formula every x rows, assign incrementing cell value

Question

I have a Google Sheet, with the first row container headers (so row references will be -1) and rows are "grouped" by every 7 rows. See below.

I've manually typed the numbers into the Image # column, but is there a way to use a formula to enter in an incrementing number every 7 rows into that column so I don't have to it for 80+ unique Captions? I'm doing this to keep track of how many unique Caption rows there are.

Answer 1

Please try, 1 in A2 and in A3 copied down:

=if(mod(row(),7)=2,A2+1,A2)