FLAG_KEEP_IMAGE_DATA

Use this if the Cairo surface to which you are rendering is a PDF, PostScript, SVG, or Win32 Printing surface.

This will make librsvg and Cairo use the original, compressed data for images in the final output, instead of passing uncompressed images. For example, this will make the a resulting PDF file smaller and faster. Please see [the Cairo documentation]( https://www.cairographics.org/manual/cairo-cairo-surface-t.html#cairo-surface-set-mime-data) for details.