Sometimes something like invisible lines cause wrong cropping. Sometimes BoundingBox information in the PDF cause wrong cropping. pdfcrop has extra options, to fix such PDFs manually. E.g. for the first image you can use:
pdfcrop --bbox "23 52 396 242" Heatplot_global_tax_attitudes_GCS_positive.pdf
to reduce the size.
The second image seems to be cropped already. So you don't need to run pdfcrop. But if I use
pdfcrop belief_mean-crop.pdf
I get the same size as the original PDF. So it seems to be correct.
However, you could experiment with options --margins and --noclip to increase the cropping result again.
BTW: The result of pdfcrop also depends on ghostscript. So if the syntax of ghostscript changes a lot, the pdfcrop also could break. I'm currently using ghostscript version 9.56.1.
--versiononly to get the version. – cabohah Feb 23 '23 at 17:35gswin64c --versionin these folders show that my version is 9.56.1). – bixiou Feb 23 '23 at 17:54