The error you are getting is because the file size is greater than the
Media.MaxSizerInMemory default setting.
This is set in your
Sitecore.config like this:
<!-- MEDIA - MAX SIZE IN MEMORY
The maximum size of media to load into memory for processing (resizing etc.).
Default value: 40MB
<setting name="Media.MaxSizeInMemory" value="40MB" />
You could patch that setting to increase the max value. But you would need to be careful with the consequences of doing that. It could cause more resources to be consumed.
I would question why an editor is loading in a 44mb image file. Ideally something like Dianoga should only be used to further optimize images for Sitecore, it should not be the only optimization. Images should be saved and made ready for the web before being uploaded into Sitecore. Depending on the image type, its unlikely that Dianoga is going to be able to compress a 44mb image to something acceptable for a web page.