What's the best image format for pasting charts into Word?

[JenniferMurphy]

When I paste (special) a chart into Word (Office 365), I am offered several image formats. I tested each one in an empty document and recorded both the file size and the picture quality (my judgment). Here are the results.

Based on this, I should use the Microsoft Graphic Object format. It has the best clarity and the smallest size. Is this a vector format?

Yes? No? ???

 

[JenniferMurphy]

PS: I forgot to explain the columns.

Column D has the file sizes after pasting the chart. Column E has the increase from the empty document. Column F has the ratio of the size compared to the smallest increase, the Microsoft Graphic Object format. Column G has my quality rating on a 0-10 scale.

PPS: I don't know how those other 3 attachments got there. I tried to delete them, but the edit time had expired. If someone can delete them, please do.

 

[JenniferMurphy]

I just discovered something unpleasant (for me) about the Microsoft Graphic Object format. It is not a single image. Each component of my chart is a separate object, which means that they can be deleted, which I just did by accident.

I am switching to the Enhanced Metafile format which is only slightly larger and id of the same quality.