Posted by dieselsanddust on Jun 12, 2015; 8:10pm
URL: https://forum.librecad.org/Scaling-imported-images-tp5711385p5711641.html

Another way to accomplish this is to first insert the image.

Then draw a single line on imported image along an entity of know length.(i.e. wall at 50 units or overall building length) Determine the length of the line drawn according to LibreCAD. In this case the line turned out to be 2 ft long.

Next select the image to scale and use the scale tool. For the scaling ratio type in 50/2 and the image will be increased in size 25x so now the image is 1:1 scale.

Finally, delete the single line used to determine the scale ratio...Not super intuitive, but it works.