Add timestamps in image picker

[Pierre Slamich]

What

• Add timestamps in image picker
  

[monsieurtanuki]

@teolemon I've already read a similar issue. The thing is that we have 2 ways of displaying "all" pictures:

1. in the product image page, below the 4 main, in columns of 3, and we display the timestamps
2. in the "pick existing image" page, in columns of 2, and we don't display the timestamps

2 ways to solve this issue:

1. re-use the same product image list - the one with the timestamps and remove the related dead code
2. sort of duplicate code in the "pick existing image" page

I have a strong preference for reusing the code that already works.

[Pierre Slamich]

Let's de duplicate for the 3 images per row + timestamps 👍