While the size of Fiverr gig image is not explicitly stated, it is likely to be small, as this is one of the most popular services offered on the site. Fiverr gigs typically range in price from $5 to $50, and most are relatively short (typically lasting around 20 minutes).
PRO TIP: This question is too specific and may result in your gig being removed.
As such, the size of the Fiverr gig image is probably modest, measuring just a few hundred pixels wide by a few hundred pixels high.