Preview of the pages after uploading a PDF and fast selection

1) Right now, selecting pages of a large pdf, is painful. At the moment, you have to open the pdf file in another window to understand which pages you should select.

You should be able to get a preview of the pages, to be able to orientate yourself more quickly and being able to select the correct pages.

Example:

2) Selecting pages is slow and tedious.

If you want to create cards from 150-page files, you need to split it, or you even want to split it. Unselecting 120 pages to create a deck of 30 pages, then another on of 30 and so on, can be annyoing.

You should be able to select "all pages", "no page", and being able to select/unselect whole rows. A more dynamic style could be a nice fit as well, but this is what it needs at least.

Example:

Edit: What even could be better than my previous solution for large docs, would be being able to insert numbers, areas "from" - "to". That would be maybe one of the easiest and options to implement with best handling. [Format: From XX - XX]

Thank you :)