I'm not sure. All I know is that Dylan said in 2014 that the site earned around 9k per month, with Pro subscriptions being the biggest source of revenue at the time, and spent 1.5k per month to run the website.
https://news.ycombinator.com/item?id=7657862
A more recent statement by him in 2021 does not disclose Imgflip's precise financial informations, but he does say that Imgflip spends less than 5k per month in infrastructure and that Imgflip "is also 80% profit".
https://news.ycombinator.com/item?id=27671164