First, in terms of other image formats, a ‘png’ file with a high resolution should work. Here is an article with more information on formats that might help:
How to export an image from DataGraph
In terms of the missing labels, we tested a couple of things on our end and can’t replicate the problem, but wonder if there could be an issue with a missing bold font.
The common fonts should all have a bold or italic version, native to the font, but not all fonts have a bold version.
In the font selector, you can check the available typeface for any font. Helvetica for example, has a number of different typeface options.
while other fonts only have a regular typeface.
For the common fonts, you can change fonts to Bold in the Style settings.
For fonts that don’t have a bold typeface, you can still select bold, but the system replaces that with the regular typeface.
If you try a common font like Helvetica, do you still have the missing labels?
Are the labels missing in the finder (hit space bar to preview) or only when you bring into another program?