First of all I like current attachments system when I can upload one picture and then I can use it from existing attachments directory. If I need use the same picture in few topics, then I only select it from directory and not needed upload again.

And best of all, I can delete images as attachments in other topics, the original image is still available in the directory until I delete the last existing copy. This is very well done, because it suits our needs perfectly.

What would be good:

We make tutorials for our customers where a certain sequence of images is maintained (for example, Step 1 - Image 1. Step 2 - Image 2, etc.). But sometimes it happens that between step 1 and step 2 I need to add another image. So I upload it, but I upload that image after the second image. So in attachment list I have Image 1, Image 2, Image 3. Yeah, it's logical, but could it be done in a way that I could change the order in the attachments as needed? That if I have uploaded images, for example, 1 and 2 and I upload 3, I would like to move it between 1 and 2 in the list of attachments?

Attatchments are just shown at the bottom of the post if you dont explicitly place them. So the answer there would be to use the + icon to explicitly place them on the page. You can then place them in any order you wish

Yes, but if would be possible rearrange attachments in the bottom list, regardless in which order were uploaded.

Im not sure I understand the purpose here. The only person who can see that is the person adding items to the post