You could try this approach
https://github.com/jkitchin/scimax/blob/master/scimax-org.el#L957 to
line 1109. It uses the external ImageMagick command mogrify to
resize the images. It monkeypatches org-display-inline-images to do
that.
Takeshi Teshima writes:
> Hi all,
>
> When I try to show inli
Hi all,
When I try to show inline images automatically resized in an org-mode
buffer, the thumbnail doesn't show (a big blank box shows where the resized
image should be) and the following errors are echoed in the "*Messages*"
buffer.
```
ImageMagick error: no decode delegate for this image forma
