Resources

This is one for the people who are interested in languages.

So, German, like some other languages, assigns "gender" to nouns. You can tell the gender from the article, which therefore should memorize the article with the word, if you ever have to memorize German vocabulary. "Der" is male, "die" is female, "das" is neuter.
Tables and the sky are male, vases and traffic lights female, books and windows neuter. There may be some weird logic behind it when you go far enough back in time, or maybe not, but it looks pretty arbitrary, and it has for most words nothing to do with biological sex. Since the same goes for animals, which often do have a sex, so that gets a bit confusing.

the dog = der Hund
the cat = die Katze
the horse = das Pferd

In consequence, any dog (and frog, and most species of bird) of unknown sex is referred to with "er" ("he"); any cat (and spider) of unknown sex is referred to as "sie" ("she"), and any horse of unknown gender is referred to as "es" ("it").
You cannot just change the article to change the gender. "Die Pferd" isn't a female horse, it's a mistake. The word for a mare is "Stute". And, yes, that is grammatically female, too; at least that much logic is in the system. Incidentally, a gelding is "der Wallach" - castrating a stud still leaves him male. Some people get weird ideas in that department.

One rather prominent example where the biological sex doesn't match the grammatical gender is the German word for "girl", that is, "das Mädchen". That's because that word is a diminutive (of "Magd", meaning "maid"), and all diminutives are neuter.

There are some words that can be more than one gender. "Gelee" ("jelly") can be male or neuter, depending on whom you ask. Other words mean different things depending on gender. I don't know many examples, but here they are:
"Die See" is the sea, while "der See" is a lake.
"Das Tau" is a rope, "der Tau" is dew. (As far as I can tell that's a coincidence, two different etymologies arriving at the same syllable.)
If someone says she's driving to Shanghai "mit ihrer Honda" ("with her(female) Honda"), she's going by motorbike, if she says she's driving "mit ihrem Honda" ("with her(male) Honda"), it's a car.

So, "the Harley" is female. "The motorbike" is neuter. That's because the German word, "Motorrad", is a compound noun formed from "der Motor", which means what you think it means, and "das Rad", which means "wheel".
This is one of the few hard-and-fast rules: In compound nouns, the gender is always that of the last component noun.

I've been trying to find some other patterns, but
Nouns formed with -heit or -keit at the end are always female - "die Dummheit" (stupidity, stupid idea), "die Wirksamkeit" (effectiveness), "die Menschheit" (humanity)

Talking about trees: There may be certain rules of the thumb you can find. While "der Baum" (the tree) is male, pretty much any species of tree whose name does not end in "-baum" and which is native to Europe is female - die Birke (birch), die Eiche (oak), die Buche (beech), die Fichte (spruce)... "Exotic" trees on the other hand are more commonly male: der Ginko, der Eukalyptus, der Baobab.
A similar pattern can be found with river names, although a bit more muddied. There are some male rivers around here, most prominently the Rhine, but a lot of rivers in Europe are female (including the Loire, Thames, and Volga). On the other hand I can't came up with a female river outside of Europe. The word for river, "Fluss", is male, too, so that might have something to do with it.

I'll leave it at that for now, hoping conlangers or writers or just apprentice language geeks get something out of it.

Dragon wings tend to be more or less bat-based, but photos of bats in flight tend to be rarer than ones of birds in flight, making studies a bit more difficult.

For birds I recommend the deviantart account of Cheryl Moore, where you can find a great number of photos of birds in flight - most of them white birds, meaning there is no pattern on the feathers distracting from the shape.

As for bats, during the last week some photos of bats drinking from a pond in flight went through the bits of blogosphere I watch. Looking up Kim Taylor brought up Warren Photographic, which has more (albeit smaller) photos of bats in flight.

On Deviantart I found one compact tutorial on bat wings by cactusart.

The wing tutorial by Kandice Zimbleman-Wang may be a bit weird on the formatting and spelling side, but content-wise I find it very helpful.

For the sake of completeness and comparison, you could look at pterosaurs wings, too. (What intersts me more after a bit of poking around wikipedia are the various head shapes, though. Fascinating.)

Thought I'd share/make note of a few (Windows [Vista]) tools I use for my image files.

Bulk Rename Utility
Exactly what it says on the box: It lets you rename files in bulk. It doesn't look particularly pretty, and the load of form fields/options at the bottom may be intimidating at first glance, but I found them pretty self-explanatory when reading them one by one.
I use the "File" field on "fixed" setting together with Numbering to change the filenames of photos I take from IMGXXXXXXXXX.jpg to 2009-07-21_XXX.jpg, which helps a lot with sorting them.

iTag
With this program I can add titles, descriptions and keywords to jpg files. This is not only useful because the Windows Explorer can search these fields, but also because various websites and scripts pull that information out when you upload them, including Flickr, Picasa, and Menalto Gallery2. Saves some work if you upload your images to several places.
iTag is my favourite among the tools I tried so far because it lets you include linebreaks in the description (unlike Picasa or the function built into Windows Explorer), and ladjust the size of the form where you enter things - particularly the fact that the latter enables you to view all keywords you entered on an image.

SyncToy
...is not only useful for images, but all kinds of documents, but here goes: A very basic program to synch up different folders. I'm sure there are better ones, but this works for me.

Sometimes, it takes some additional input to understand advice.

One thing is the "draw lines with one long stroke, not by adding up lots of smaller lines" one. I never understood how that would be possible, until I came across advice on how to improve your handwriting saying you should use your shoulder and back muscles, not your wrist and fingers for writing. Doesn't mean I can magically DO it, but at least I have some idea of what I might try to learn.

Another are the scribble pictures. I remember doing those in art class back at school. Here's the idea:
You scribble random loops and lines on a piece of paper
Then you look at it, and turn it into an image of whatever you happen to see in it.

I thought the idea was drawing over the lines as they were on the paper, so mostly I ended up with blobby rubbish, like snakes without heads, three-story mushrooms, or faces like this one:

Then I came across a tutorial at deviantart, which is not safe for work due to nudity, and looking at the example... You could add stuff. You could turn a circle into a face, or a hand. Yeah, I see how that might actually be fun, rather than frustrating, and result in more interesting images.

[caption id="attachment_392" align="aligncenter" width="500" caption="Here's the original scribble; lines darkened digitally to make sure they show up; actually I use very light pencil lines. I also turned the sheet around a bit until I spotted something..."][/caption]

[caption id="attachment_394" align="aligncenter" width="500" caption="I saw a head and a wing, and went from that..."][/caption]

[caption id="attachment_395" align="aligncenter" width="500" caption="Added feet and tail and refined some details. Would look better if I traced it on a clean sheet in ink, but I'll leave it as the little warmup practise it is."][/caption]

I guess that's a good time to upload some of the more interesting results of those warmup-practises.

The following four are other sketches, from my figure drawing class, and people who want to avoid nudity should avoid those.