Yes. You can scale the image at insertion at the Tool Options bar above the drawing area, or afterwards with the normal Scale command, or using Properties and changing the dpi value.
Of course you have to know a real length in the object to be able to measure that length on the inserted image and then calculate a scaling factor. Or if it is a scan of a physical drawing you might know the dpi it is scanned with. Even if you haven't scanned it yourself the value might be written into the file. Probably something like 300 or 600 dpi. An image viewing tool like Irfanview shows it.
In LC 2.1.3 if you use the normal Scale command the image will seem to be disappeared afterwards. An Auto Zoom brings it back.
I have read the LibreCAD manual from front to end and teaching readers the details of printing is not there. Why? I've read many of the LibreCad printing threads and I'm coming up with absolutely nothing. Nothing! I mean nothing!!! I've drawn a business card that is to scale 1:1. As you may know business cards are 3 1/2" X 2". I need step by step instructions on how to print this out full size 1:1. Print Preview / Scale / ??? I'm not seeing any of this! And when I right click on the LibreCAD icon it doesn't tell me the latest version. What the heck?!? Why have you made printing so mysterious?
I down loaded LibreCAD only a week ago, so I'm assuming I have the latest release of LibreCAD.
I know this software is free, but I'm still disappointed. Not being able to print a drawing because of lack of instruction is very sad to me. LibreCAD, at least for now is worthless to me.
Please remember I have read many threads in the LibreCAD Forum regarding printing. I find no step by step instructions that works in my LibreCAD software when I see the application on the LibreCAD working screen.
This is for version 2.2.0 (RC at the moment), but is basically valid for 2.1.3 also.
If you can't see the Print Preview / Scale stuff at the Tool Options bar you might have killed it accidentally. Check whether Widgets - Toolbars - Tool Options is on.