Lens Studio 5.2 and 5.3 are both missing the 2D animation from files option in the asset browser. Today I will walk you through a workaround to import them again.
Getting the Option Back
There actually is a Lens Studio 5 version with the 2D animation from file option. It is LS 5.1.1.
We need to download this version and make a second install.
Go ahead and download the 5.1.1 release here: https://ar.snap.com/download/v5-1-1
Once downloaded, run the installer but change the destination location to a new folder with a different name.

I named mine Snap Inc 5_1_1.
Proceed through the rest of the installer then find where you installed it and open the Lens Studio.exe

Creating the Animated Texture
Create a new project in this 5.1.1 build and head to your asset browser. Click the plus button and find “2D Animation From Files”

Ta da! The feature works! Import your animated texture as normal on the window that appears and click ok.

It will create the asset. Head down to the asset browser again and right click the animated texture then choose “Open in Explorer”

Importing to 5.2+
Next keep your explorer window ready but minimize it for now. Then open your newer version of Lens Studio and enter the project you wish to use.
Do not close the 5.1.1 instance yet unless you save the project we created earlier first!
Now open up that file explorer window again over your 5.2+ Lens Studio. You should see an animation.t3d file.

Drag this animation.t3d file into your asset browser

That’s it! You should see your animation imported as an animated texture now!

You can now use it as you normally would and close the 5.1.1 project. Enjoy!