P: A way to create a custom crop overlay.

@volkerkunkel What a great workaround! And, isn't it silly that we still have to use a workaround for this. Thanks for the tip.

It's 14 years later and a feature that would be incredibly useful to professionals who do volume work is still not available....

Custom overlays? In this decade? Nah. Btw, idea from May 18, 2011. Shame.

Too bad Adobe isn't a well-funded, hugely-profitable tech company with a bottomless well of excellent developers with relevant experience creating photography-related software that promptly adds features that customers ask for.

Seems contemptuous of customers who have been asking for this for over 13 years.  🤷‍

This request is still very relivant.  I don't wish to outsourse my headsizing, and want to have control over it.  I am happy with Skylab for my background extractions, glass glare removal and retouching.  However, I will continue to do my own headsizing.  I would definitely cut down my workflow though if Lightroom had this feature, as I run everything through there as my first step.  

This thread and request is so old that there are now AI tools that can do this for us. For those tired of waiting check out SkyLab

This is a very good idea, which must be super hard to implement or what are the excuses, why this is not a thing yet? Lightroom and Photoshop, both has different way crop overlay settings. Instagram's peak period is probably over, but if this is implemented in next 5 years, we may still use it. Just imagine this: you are cropping 5:4 and see also 1:1 overlay. Yes, this is possible in LrC, but not possible in Ps. Custom overlays? In this decade? Nah. Btw, idea from May 18, 2011. Shame.

Tanya - I'm looking for the same thing for the exact same reason. Upsetting to see that two years later it still hasn't been added.

LrC has a loupe overlay so you can display your own custom image over the top your images. 

This is a similar request.

https://community.adobe.com/t5/lightroom-classic-ideas/p-a-way-to-create-a-custom-crop-overlay/idi-p/12394151

However, in 12.3 on macOS whilst you can display the overlay as soon as you enable Crop overlay tool the custom image disappears.

The workflow here is trying to crop a sequence of images consistently. So you setup an overlay so you can align things correctly - for example you want a product in the same position between shots. If you are making your own overlay you might also define a bounding box in which you want the object to appear.

Ideally the reference overlay you make is targetting the final cropped image. So having the Loupe Overlay sensibly visible when you are doing the crop is important. By sensibly, I mean that the overlay appears relative to the crop rectangle, not the original image. I want to make sure that certain elements in my final crop are aligned perfectly. There are times when you need more accuracy than a coarse grid and if you do have the grid enabled, counting boxes over several images slows you down.

Right now it is cumbersome having to switch between tools to check whether you have actually pin pointed the crop properly.

I'm using an app called 'Red Lines Tools' (from the Mac Appstore). It's not working well in Crop-Mode, as the image size varies from image to image with no way to set it consistent. But it's working in full-screen view. So with a lot of going back and forth it's only just usable.
But Lightroom should do better! Please, please provide options to set custom crop overlays! It will be a lot of help for us portrait photographers!

C'mon Adobe.  Please give us this option.  A custom overlay for those of us doing volume photography is a must.  Give us the option to adjust transparency of that overlay and it will be a huge timesaver for certain workflows.