Exported image should contain all information.
Exported image is cropped and parts of the labels are missing.
I did a bit of hacking on the CSS in the browser and increasing the width of the elements resulted in a full image (after some window resizing to get the canvases to catch up). It may be possible to clone the relevant elements and resizing them before making an image of them. At least that looks like how it's done to me.
A workaround is to resize the window before clicking "Export as image".
Exporting images, such as the graphs, is a good, quick way to show statistics. You can't really do that if parts of the labels are missing.
Hi @sebastian-berlin-wmse, thanks for reporting this issue. I can confirm that if any part of the chart canvas is being cropped before clicking export as image then the resulting exported image will also be cropped. As you note it's easy to workaround by maximizing the widget before export, but it would be much better to have this happen automatically as part of the export action.