This is kind of borderline here between a wishlist item and a bug-
report, but gimage-viewer needs a tessdata package as a dependency,
since otherwise it can't do any OCR scanning at all (no languages
available). tessdata repo is available at 
https://github.com/tesseract-ocr/tessdata/.

A work-around is to (1) clone the tessdata repo; (2) link it to
~/.config/tessdata, and then (3) edit your gviewer settings to use
local user paths instead of the default global paths.

My system info:

christopher@theoden ~$ neofetch --stdout
christopher@theoden 
------------------- 
OS: Guix System 3f1b2bd322b6cdba99a43d08e5e8464f7424cbc5 x86_64 
Host: OptiPlex 9020 00 
Kernel: 5.10.18-gnu 
Uptime: 2 days, 6 hours, 3 mins 
Packages: 91 (guix-system), 99 (guix-user) 
Shell: bash 5.0.16 
Resolution: 1920x1080 
DE: GNOME 
Theme: Adwaita [GTK2/3] 
Icons: Adwaita [GTK2/3] 
Terminal: .gnome-terminal 
CPU: Intel i5-4570 (4) @ 3.600GHz 
GPU: Intel HD Graphics 
GPU: AMD ATI Radeon HD 8490 / R5 235X OEM 
Memory: 3260MiB / 7871MiB

--
Christopher Howard