I can think of three ways to handle this two will require work some work...one less but need to get lucky.
1) Create a new checklist and insert set (rename the current one by changing the title by adding TO BE DELETED on the end) then move over the data and images by deleting cards without images and transfering data, and moving images and data with those that have images. Once that is done delete the TO BE DELETED SET.
2) Click on insert card and scroll down to the bottom. Green button sasy "Append to checklist." Append the correct checklist to the end and do all the moving and deleting within the set.
3) IF the players in the checklist are EXACTLY the same just numbered different change the card numbers and resort.
EDIT: Looking at the three images uploaded I don't think the Denny McClain (which is the sample image) is even of the OPC poster. Colouring and sizing is different. Would definitely not be a shock if so going by the uploader's reputation.