Image block module translate
I believe the image block module is not yet fully compatible with i18n module and you will need to apply the patch in this issue which according to the posters is reviewed and ready to be committed.

Alternatively you can install nodeblock and create a content type (i.e. block) and use it as a nodeblock and you will get all the benefits of nodes and blocks.  Therefore you can add image fields or any other fields that you need and after creating a node of that content type you will be able to add it in a region of your theme like a normal block. Nodeblock supports translatable content (Contrent translation with i18n and Entity Translation).