Feature - Side-by-side image comparison [Not solved yet]

[ru-bem]

Just a simple request: a way to view / compare two or more images side by side, like IrfanView or Butterfly Viewer.

[riyasy]

Glimpse of what I am trying to do:

When multiple Fly instances are enabled, only the first Fly instance runs in full mode.
Any additional Fly windows will run in single limited viewer mode, opening only the requested file.

The first Fly instance provides the full experience - including the thumbnail bar, folder navigation, settings management, and caching system. Subsequent Fly instances are intentionally limited to simple viewing.

This choice is deliberate.

Fly is optimized to use as many system resources as possible to achieve instant image loading and smooth navigation. When browsing a folder, Fly aggressively enumerates files, generates thumbnails, and fills the cache to make scrolling and switching images extremely fast. If multiple full Fly instances attempted to perform these tasks simultaneously on the same folder, they would end up competing for disk access, CPU time, and cache generation, which would actually make the overall experience slower rather than faster.

Another challenge is shared state management. Components such as the settings file and the image cache are designed to be managed by a single primary Fly instance. Allowing multiple instances to read and write to these files simultaneously would introduce complex synchronization problems and could easily lead to corrupted settings, cache conflicts, or subtle bugs which could be difficult to handle alone for me..

[riyasy]

Fixed in 2.5.19 (Store). Will soon merge to Github MSI.

[riyasy]

Fixed in 2.5.20

[ru-bem]

I mean... That was not what I was trying to say... Side-by-side comparison and multi-instance are different things, aren't they? For example, in IrfanView you can select two images and compare them. You can even zoom in and out and scroll through the images.