Like everyone else above, I would love to see this as a native function in Asana. Definitely one of the top missing functions in the program in my opinion.
In the meantime, here is the workaround I found to work the best (in keeping the original Asana timeline graphics)…
Step 1: Open Asana via web using Chrome
Step 2: Click on the “public sharing” button at the top right to create a link. This will allow you to create a link to view the timeline view in a slightly cleaner format - ie. white background, etc. (Step 2 & 3 are’t a requirement in this workaround - just a graphical preference, FYI)
Step 3: Paste that link into a new browser tab to view the timeline view in new format
Step 4: Zoom out to capture all of the content in your timeline (cntl + minus)
Step 5: (KEY STEP) Now rather than doing a default screen capture of your timeline, which would pixelate all of your graphics and text follow the instructions at this link to do a high-resolution screen capture. I would use at least 1920x1080 for the capture, per the link’s tutorial.
The first time you do this it will take all five steps. Then after you have the custom/high res screen capture setup in Chrome it should only take a couple steps.