 This is all well and good.  These are excellent things to know about a character you've created, and I applaud the effort.  However, if you tell your readers all of this in two paragraphs as you introduce him, and then promptly kill him off less than a page later (or send him off-camera for the entire rest of the story because he's not actually part of the story) then you're going to lose your audience.

Descriptions are always important in your writing.  Descriptions set places in mind and give faces to characters and bring moments to life.  Do not, however, get too bogged down in trying to describe every last detail of a scene that you forget what's going on, or worse, that your reader does.  Taking a moment to reflect on the history of a particular piece of art is fine, especially when it was created by someone dear to your character and thus showing more detail of the character's interpersonal relationships.  Taking more time to go additionally into its historical and aesthetic value may even be acceptable, including religious iconography related to the piece and references to Renaissance-era painters with similar themes.  Doing all this while the character is in the middle of a climactic swordfight is alas not advised.  Everyone will be surprised by the sudden epee to the heart, especially your easily-distractible character.

Related: you are not Victor Hugo.  Do not spend two hundred pages of your fanfiction giving us the historical background of Franciscan friars and their presence during fifteenth century England, simply because Harry stopped to look at the painting of the Fat Friar for a moment and then went on his way for the rest of your eight hundred page story.  Or do, but I won't be reading.  No one cares how smart you are.  You don't need to show off.

None of this is to say you shouldn't explore or experiment.  You can tell a story entirely in third person past tense without a single line of dialogue or direct action.  You can go on long tangents; one of the joys of reading is learning something new and unexpected while being entertained.  That last word's the kicker.

Your reader has clicked open your story because s/he wants to be entertained.  S/he wants a quick (or longer --- Dr. Merlin likes well-written epics as much as the next fan) hit of the same stuff s/he sees in the canon.  Maybe that's the interplay of two particular characters, even divorced from the canon setting (perhaps an SGA John/Rodney AU set in a NASCAR venue, for example).  Maybe it's the witty banter like in Buffyverse or Aaron Sorkin's shows.  Maybe your readers are madly in love with any character named Hermione, regardless of how she's written, be it rocket scientist or valley girl.  You're there for the same reason, and you're not just writing to satiate your audience but to scratch your own itch.
