I have a document with several images from a few different sources. I'd like to indicate different formatting options for each source. I understand I can use graphics groups for this, but I don't know how I can enter complex formatting command for this.

To give an example of a complex command, for a given group, I'd like to have the image width equals the smaller of 75% of the size of the original image, or the line width.

From another question, I got this handy macro, which works well across the whole document:

\setkeys{Gin}{width=\ifdim 0.75\Gin@nat@width>\linewidth

However, trying to paste that code into the LaTeX Options text box in the graphics settings dialog does not work.

Any pointers?

  • By "groups" are you referring to (say) a section within your document? Different sections refer to different groups?
    – Werner
    May 15, 2015 at 0:27
  • @Werner No, groups are ways to tag graphics objects so that they share formatting settings. If you change the settings in a graphic that's in a group, Lyx makes that change in all the other graphics in the same group, regardless of where they are in the document. May 15, 2015 at 8:55

1 Answer 1


Best here would be to define group-specific key-value options. This would allow you to set a single option associated with the group, while LaTeX manages the back-end setting for the option.

As an example of this, add the following to your Document > Settings... > LaTeX Preamble:

  \setkeys{Gin}{width=\ifdim 0.75\Gin@nat@width>\linewidth

The above* defines a "boolean key" groupAoptions which you can now call using

enter image description here

Of course, now you can include many group-specific options into the single groupAoptions key, if you wish.

* Note there is no requirement for using a \makeatletter...\makeatother pair in the LaTeX Preamble for LyX, as this is inserted automatically.

  • Stellar. Worked like a charm. :) Thank you also for the \makeatletter tip May 18, 2015 at 9:53

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