# Fast PNG embedding using xetex

As discussed in this post and also this post, `pdftex` has the ability of copying PNG files as-is if they are in the right format. This is very useful for me (I’m experimenting with 1024×786px background images for my beamer slides).

My files are in the right format, because compiling with `pdflatex`, I see

``````</home/jojo/texmf/tex/latex/substrate-beamer/substrate0.png (PNG copy)>
``````

in the `.log` file.

But compiling the same file with `xelatex` (which I’d like to use for the proper font), compilation takes a lot of extra time (and does so only if I include the pictures), and there are no indication in the `.log` that the PNGs are copied. So I assume that they are extracted and recompressed, which explains the long wait.

Does `xelatex` have different requirements for PNG files to be copied? Or does it simply not support this feature?

• I made a test with a 'huge' png file from OpenClipart.org and indeed, `xelatex` takes about twice as long as `pdflatex`, but `lualatex` is as fast as `pdflatex`. Perhaps that's a way to bypass the bottleneck and being able to use the other fonts as well – user31729 Aug 29 '16 at 13:31
• I never really got into the `pdftex` vs. `luatex` vs. `xetex` issue… it seems that `luatex` likes my file, and indeed is much faster. Thanks! – Joachim Breitner Aug 29 '16 at 13:33
• I basically never use `xelatex` or `lualatex`, so I can't provide a reason why `xelatex` enters a `Windows idle-loop` there ;-) – user31729 Aug 29 '16 at 13:35