We are using the .net framework and C# to generate the documents. InsertHtml is replacing images with a placeholder. This used to work fine and we have not changed any code, but our client has come back to us after using it over and year and said that some of the images are no longer displaying. What they get is just a white box with a red x, where the image should be.
The rest of the document seem to work fine, it is just that some of the images are missing. We have tried updating to the latest stable nuget package, with no success.