Updating: If you are updating (to 0.9.0.2) from a prior release, you probably have to restart the app twice (after installing Saving Launcher). Context (Right-click) Menu Items Provided:

Open Image… (before WebExtensions used to be after View Image): to open an image (having saved it in a customizable primary IA folder (this also works for images with an image map))
Save Image (after Open Image... (since 0.2.9)): to save an image in a pre-determined folder without opening it (this also works for images with an image map)
Open Image (using #TmpD/ia)… (after Save Image (since 0.7)): to open an image (having saved it in a customizable secondary folder (this also works for images with an image map))

Supported Operating Systems & Default Image Viewers:

Windows 10, Windows 7 & Windows Vista (32-bit & 64-bit (OS & app)): Windows Photo Viewer
Windows XP: Windows Picture & Fax Viewer
Linux (32-bit & (since 0.8.3) 64-bit (OS & app)): eog (since 0.7; gThumb prior to 0.7)

Configuration (Optional Customization (since 0.3.1-gecko37 release)): A. Paths:

Image-viewer to open images with
Folders to download images to:
- primary
- secondary
Whether to reflect secondary path on UI (since v0.7; default: yes)

B. Variables (Directory Service definitions (reflecting changes made in v0.7)):

#OS_PIC used in default primary downloads folder, #TmpD used in secondary downloads folder, #ProgF used in viewer command for Windows 10+ can be replaced with a literal path of your choice (in which case don't include # sign in the path). If Saving Launcher doesn't recognize a variable, it falls back to looking up an environment variable corresponding to it.

Supported Locales:

crh - Qırımtatarca (Kırım Tatarca)
en - English
fr - Français
it - Italiano
tr - Türkçe
tt - İdíl-Ural Tatarça

P.S. All other OSs (in particular, Mac, and Solaris): not officially supported as of now due to lack of time, etc. to provide native component builds for them.