Images, Export, ExportString and ExportForm do not work on version 14.0

[s4m13337]

On Wolfram Engine version 14.0, when trying to return an Image or its Base64 encoded version using ExportString/ExportForm, the kernel keeps evaluating the request forever.

For example, this one keeps evaluating indefinitely:

ExportString[
 Histogram[RandomVariate[NormalDistribution[0, 1], 200]], 
  ColorFunction -> "Pastel"], {"Base64", "PNG"}
 ]