It centers, but does not resize. Both when set to a specific percentage or left on automatic the SVG never changes from 100% zoom.

Additionally, because of being centered if you zoom manually the SVG will go off the edge of the screen and the user is not able to scroll far enough to see the entire graphic as firefox doesn't handle it like a normal image.

Can't use local files.

Can't test this extension because it doesn't support local files and the only SVGs I need to view are stored locally. The hard top/left rendering of the FF built-in viewer is nasty and I'd be enthusiastic about CenterSVG if it worked with local files.

There are two things I would love to be done:
1) Ability to set background color as yours is too dark and black images are poorly visible
2) Extension works only with SVG files that are browsed online, when I open saved SVG it's not affected by extension. I collect some SVG's for the work and need to browse them. Using Firefox for that purpose will be great.

Otherwise it's a useful extension indeed. I don't understand why all browsers center bitmap images, but doesn't center SVGs.