We have recently released Aspose.Words Cloud 20.10. And I am unable to replicate the issue with it. Please note I was unable to access your last two images due to the expired signature, so I replaced it another remote image link.Testmailmerge.zip (382.1 KB). Please double check with the latest release and confirm.
You can define image size in the template as follows:
The format is case-insensitive. The values of the width and the height should represent double constant values using the dot as the decimal separator (i.e. using invariant culture). Negative values should be used to indicate that the original values of the corresponding image dimensions should be used. If no unit is specified, points are used by default. If a unit other than “pt” or “%” is specified, then the image size parsing is considered to be failed and the original values of the corresponding image dimensions are used.
Hopefully, it will resolve the issue. Otherwise, please share the problematic template, data file and expected output. It will help us to understand and address your issue exactly.