In my admin/config/media/image-styles section I see only three presets that I can edit:

node_gallery_display
node_gallery_thumbnail
node_gallery_api_admin_thumbnail

But for my website I need more than 3 adjustable presets. On some pages I need square thumbnails. On some rectangular.
How is it possible to make more?

I created in file styles admin/config/media/file-styles the new presets. And I can use them when I edit the display of the image on its page.

But when I try to adjust the view of image files in a view I change the settings of the field

FIELDS
(Gallery Item) Content: Gallery Media

Then I choose

Formatter
Media Colorbox
(because I want them to open in a lightbox)

File view mode
there are options

Default
Teaser
Full Content
Preview
RSS
Search index
Search result
Colorbox
Node Gallery File Display
Node Gallery File Thumbnail
Node Gallery File Cover
Node Gallery File API Admin Thumbnail
Tokens

1) So, where is it possible to change to size of image file that I can see using
Teaser
or
Preview
options?

2) Or adjust Node Gallery File Cover size?

3) Or make more than 3 adjustable presets that would be possible to change?

Thanks in advance!