Side-by-side comparison of images

I just installed the demo version of FRV and I'm really impressed by the superfast management of RAW files.
I only miss one feature that I consider essential, a side-by-side comparison of two or more images.
Is this feature present and I just didn't find it? Or is there any workaround to use a similar feature?

Dear Sir:

This feature was asked by our users for many times. Unfortunately, current FastRawViewer is built around single 'main window' and simultaneous several images display requires deep program internals re-work.

This is scheduled to FastRawViewer 2.x (no ETA right now, definitely not this year).


Alex Tutubalin/FastRawViewer team

If it were possible to run separate instances of FRV then a side by side comparison could be made. I do this with Preview on Mac often.

Dear Sir:

Standard Mac apps (including FRV) are single-instance.

It is possible to get around the limit by running FRV executable file from Terminal, as described in our manual: (section: launching several instances)



Alex Tutubalin/FastRawViewer team

The recommended method of starting a second instance on MacOS Mojave required a second instance of Terminal but that is easy and that did work.

I'm trying out FRV and I already miss the side-by-side comparison that I use frequenly during culling images in Lightroom. I do a lot of wildlife photography and I frequently take a large number of photos of the same subject. For example, I may take a burst of images of a bird in flight and then want to choose the best wing position by comparing two images side-by-side. Lack of this feature is a real showstopper for me. Any update on when this feature might be available?

I approve the request from two years ago (Side-by-side comparison of images), that's one of the only thing that miss in this great software.
You said definitely not this year in 2018, what about in 2020 ?

I wish to add my request for a multiple image side-by-side image comparison similar to that in FastStone Image Viewer and XnView MP. These examples contain, for example, the ability to sync zoom and pan for the compared images, something that is impossible when multiple instances of FastRawViewer are tiled for comparison.

Hi there, I would also love the ability to compare images, even if the function is limited (not able to sync zoom pan etc). It would be really helpful to roughly compare images in order to choose ones with similar composition when going through different product shots. I'd be willing to pay to upgrade. 

the ability to sync zoom and pan for the compared image

It's such as a waste that we don't have proper comparison option, but even with single image workflow... maybe you could provide option to remember last zoomed position of image? This would make comparison of similiar photos easier once you roughly adjust positions of images in question. I only have Lightroom 5 and this feature works fantastic even though software is not as fast it makes comparing and culling similiar images easier (not to mention it have proper comparison tool which, once again, would be awesome to have).

If Preferences - Zoom - Image zoom on next file is set to Keep zoom ratio than zoom and posizion are preserved.

Note: FRV versions prior to 1.7 (Release Candidate) will switch scrollbars off when moving to next file if zoomed. This is fixed in 1.7.0-1682 available from:


Alex Tutubalin/FastRawViewer team

If Preferences - Zoom - Image zoom on next file is set to Keep zoom ratio than zoom and posizion are preserved.

yes, but if image differs e.g. moving plane over sky and I would like to compare sharpness for moving subject I would like to set offset of images independently, so I would love FRV to remember position of each image.

I second this request. It would be very much appreciated for fast image culling to be able to have a comparison mode, one picture left, one right with all viewing settings like edge detection, shadow/highlight inspection mode synchronized between the two. 

I third this request!
Looking at close crops of bird pics, I need to keep the head centered between different images. Thank you.

2- and 4-window mode is implemented in FastRawViewer 2 (now in beta1):

(download links are at page bottom).

Here is detailed description of multi-window mode:


Alex Tutubalin/FastRawViewer team

Hi, just wanted to thank you for this implemantation. It's been something we were asking for a while and it's working great. Thanks.

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