I usually do it, I put the circle green logo with the text fiverr logo on the image of my gig. Never tought it is essential for visibility, but I like it… 
Well, I found an article on Quora, this one:
https://www.quora.com/How-can-I-increase-sales-in-Fiverr
where at point 9 he says:
“Use 3 images of high quality which explains that what the gig is for and don’t use fiverr logo on any image.”.
Why? Do you agree with him? 
I’ll get back to you on that, but at a glance there are a major problems with that list. The first issue I take is that it outright tells you to lie.
Of course you can’t use fiverr logo. First it’s quite unethical because you are not fiverr representative to use their logo and you are not fiverr “approved” staff.
Secondly there was a period a couple of months ago where fiverr was delisting all gigs that was using their logo on images or level badge or 5 stars
Strange, because I’ve seen many sellers active from many years that use Fiverr Logo. By the way, I’ve just removed it from my Gigs!
this 
and they still might be doing this.
it’s really getting frustrating when people start saying “but others also using it”, “but others also breaking rules”, “but others also providing service that is not allowed”.
Sooner or later those people also will be caught. So why to put your account at risk just because someone else is breaking rules.
well done!
Use a very good photo of yourself, a cartoon version of you, or a logo of your brand.