Hi there!
I normally just read all the fascinating and instructive information posted by the members of this great community (information that wouldn't be available anywhere else, I guess), but as a native speaker of German and a teacher I thought I would chime in and try to contribute some insight regarding the exact meaning of Schmeling's dedication to the lucky addressee of the photo. First, it isn't written in "old German" (which actually once existed and was in use until about 1940 - and which is definitely nearly impossible to decipher even for Germans born after the 1950s like me...). Max used "modern German" (= the Latin alphabet as we know and use it today) and the dedication which reads "zur freundlichen Erinnerung" can be literally (but also accurately?) translated with "for friendly memory/memories". So "freundlich" just means "friendly" in English, not "friend" or "friendship" and Max chose a quite formal wording for his dedication (which makes me doubt that Mr Valk was a close acquaintance or even a friend of his).
Thanks for reading this rather brash stuff and take care!
Dirk Holtschmidt