Batch rename list of files based on other properties?

Question

I have two folders. Folder A contains high resolution images and folder B low resolution images. Images of Folder B are located in the server. I need to change all images to a higher resolution version contained in local folder A, without changing the file name.

I can upload and replace the images from folder A to folder B via FileZilla but I need before to rename all images with the same name as folder B.

Unfortunately images have custom and unique names. What would be the best path to follow on this specific case?