Need to randomize 3 blocks, and for each block I need to add the same branch. How can I do it?

Is there a reason you created a block for each of your three pictures? To me it sounds like you have: Picture A with one yes/no question Picture B with one yes/no question Picture C with one yes/no question Those could be formatted into Block: Pictures so that there are three questions (one for each picture) where the question text holds both the image and question wording. Those three then can be shown in a random order by going to Block Options and choosing Question Randomization, Randomize the order of all questions. You can then either use branching logic on blocks to get your follow up questions. Or a new block with display logic to get to the follow-up question. You would use this approach if you want them to see all the pictures before the follow-up questions. But if you want them to see one picture then the follow-up questions for that picture before randomly selecting the next picture to have them say yes/no to, that would be set up differently. I can't advise without understanding the logic you are hoping to have on subsequent branches.