How to remove image counter in Blogger´s photo galleries?



I have been trying to remove the image counter in a blogger image gallery but I can´t. When you click on an image in blogger the image gallery appears and you can see a counter which indicates how many images the gallery contains, for example:

I would like to get rid off it or make it invisible. You can see this kind of image counter on the following blog:

Does anyone know how to remove it?

I would really appreciate an answer

Thank you!