If there is another Bet Knesset to pray in then you should, otherwise you may pray just not in front of the picture and close your eyes so you will not get distracted by the picture.
Explanation:
The Abudraham writes the Rambam was asked what is considered a barrier between you and the wall when saying Shemoneh Esrei? Is a tapestry on the wall is considered a barrier? If these have pictures woven in them is that a problem?
He answered the reasons of not having a barrier between you and the wall is so there shouldn’t be something which might distract him while praying. So, having clothing is not forbidden to pray in front of them. However, it’s better not to so you don’t get distracted and the tapestries one may start looking at the pictures woven in . It is better to close you eyes if you are stuck in this situation where the is a picture on the wall in front.
We can see according to the Rambam there is no prohibition to pray in front, but one should close his eyes the e whole time. So rules the Shulchan Aruch 90:23.
The Magen Avraham comments: it is forbidden to have drawing in front of a person in the bet Haknesset, rather they should place them above the heads of people. The Aruch Hashulchan explains meaning above three amot which is the height of a man.
The Machatzit Hashekel adds that it is not just for Shemoneh Esrei but the whole Tefilla it is distracting.
The Shulchan Aruch YOD 141:6 writes that it is permitted to draw pictures of animals and birds and fish and trees even if they are three dimensional. The Taz adds that Hagahot Ashri in the name of Rabbeinu Elyakim that one should draw these things in a Bet Knesset since it looks like one is bowing down to them.
In light of the opinion of the Taz, the Acharonim argue if it is appropriate to put images of lions and other animals on the Parochet of the Aron Kodesh.
The Aruch Hashulchan writes that is better to not have the mages of animals in the Bet Knesset, and especially to have pictures of people.
It seems that the Aruch Hashulchan was very stringent when it comes to pictures of people.
The Divrei Malkiel (6:2) rules that it is forbidden to have pictures of people on the walls of a Bet Knesset, and therefore anyone who fears G-d should stand up and remove any picture from the wall of the Bet Knesset.
So too the Ohr Letziyon (1:7:11) rules that a person should not pray in front of images of animals even if he closes his eyes since it looks like he is bowing to the images or the pictures he may just close his eyes.
It seems that the pictures of men and pictures of animals have the same Halacha ad if one is permitted so is the other. Since we only have a worry that it either it is a distraction or it looks like you are bowing. Either we are worried about it or we are not.
Therefore, if you hang the pictures in the back of the Bet Knesset it would seem that that is not a problem. The Yalkut Yosef rules though (Tefilla vol 1 pg. 213 halacha 43): One should not hang pictures of Gedolei Yisroel on the walls of the Bet Knesset so as not to distract the congregants. If you are in a Bet Knesset where they did you shod try to take the down or at least tell the Gabbaim that they should hang them in the back of the Bet Knesset not in front of everyone. It seems that it is better not to hang them at all.
