Trim white-spaces when parsing image references

[lcarva]

Sometimes, an image reference may contain a trailing white-space, let's make sure those are still properly parsed.

[zregvart]

Are situations where white-space is allowed? Could being lenient about white-space lead to more issues downstream?
I would argue that white-space should not be allowed in image references and that EC should not be lenient about it. It should be easy for the producer of the image reference to trim the white-space on their end.