Fix images in enclosures without MIME type (#3361)
Fix images in enclosures without MIME type (#3361)

#fix https://github.com/FreshRSS/FreshRSS/issues/3358
Assume enclosures without a mime type, without a length, but with either
a width or a height are images
marienfressinaud/FreshRSS,Alkarex/FreshRSS,FreshRSS/FreshRSS,aledeg/FreshRSS,FreshRSS/FreshRSS,Alkarex/FreshRSS,marienfressinaud/FreshRSS,marienfressinaud/FreshRSS,FreshRSS/FreshRSS,FreshRSS/FreshRSS,aledeg/FreshRSS,Alkarex/FreshRSS,marienfressinaud/FreshRSS,Alkarex/FreshRSS,aledeg/FreshRSS,aledeg/FreshRSS