So this is what free speech looks like...

iStockphoto. Stock Photographer Training Manual

Do Not Submit:

Camera Shake
Reflections
Harsh shadows
Underexposed
Overexposed
Lens flares
Purple fringing
Noise (and pixel/color distortion)
Compression (*jaggies) "jaggies" are large square patterns in the image.
Cross processed colors
Simple one process filters, such as cutout.
Overly high contrast that compromises image quality
Jagged edges
Extreme feathering
Distracting Shadows
Scan that appear fuzzy/out-of-focus
Scans that have visible dust, hair &/or scratches
Scans with noise distortion
Multiple color versions
Similar angle series
Exposed genitalia, pubic hair, female nipples
Partially exposed genitalia, pubic hair, female nipples
Sexually suggestive and potentially offensive subjects

Uploading any of the following is strictly prohibited and may result in a lifetime ban or legal action:
a. A photograph of a photograph.
b. A photograph that you didn't take.
c. An image you found (on the web, from a book or magazine or other printed object).
d. Desktop patterns that are found.
e. Stock photographs from other stock agencies.
f. Tracing (illustrations) or creating unauthorized derivative work.

Do not submit:
logos, trademarks, company names, product names, product brands or trademarked and patented designs
most modern toys, many brand name watches, brand name computers and other licensed products.
Paintings, sculptures, any object in a museum, any object in an art gallery, including public sculpture, some architecture, advertisements, other photography (a photo of a photo)
Modern maps, documents where names are mentioned, computer screens (interface and icons are copyrighted).
Traced illustrations based on stock photography, fashion editorials, etc, that you do not own the original copyright for.
Embedded Copyright Notices
Government & Military Property...
Agency insignia, military decorations, golden eagles, Presidential seals, flat scans of US currency.
Trademarked Buildings, Monuments & Landmarks:
The intellectual property laws of this category can sometimes be confusing. It is best to research the structure before uploading it to iStock. For instance, photographs of the Eiffel Tower during the day are legal for resale, but not night shots (showing the light show).

Images that iStock does not need:
Your dog or cat
He's adorable. Send a picture to your mom.
Flowers
iStock now possesses the definitive online collection of files called ‘flower’.
Flags
We can now proudly say we have every country covered.
Photos of your feet, socks, etc.
Try looking up with your camera instead.
Your immediate environment
Get up, move around a little. Keyboards, mice, cables, compact discs, floppy discs and monitors are covered.
Light Blurs
Great for fun and experimenting...
Brick walls
The Wall came down in 1989. Get over it.
Close-ups of fire
It's for your own safety.
Close-ups of eyes
They scare small children.
Symbols (!$%@)
You see it in every e-mail.
Sunsets & clouds
Very pretty, but...
Forest Snap Shots
We love nature, but...
Airplane Wings (& out the window shots)
In the end, they seem to all look the same.
Your Shadow
Try another route of dodging the model release.
Overly simple 3-D & Bryce renderings & Photoshop backgrounds
Challenge yourself a little.
Photoshop Backgrounds
Fun to experiment, but they're not quite stock.
Overly simple text
Let people pick out their own fonts.

Our Content License Agreement includes several restrictions. You may not do anything with the Content that is not expressly permitted. You may not provide a copy of the Content, or any portions thereof, to anyone or allow anyone to gain access to the Content, or any portion thereof, except as permitted above. For greater certainty, you may not:

(a) use the Content in design template applications for resale, including, without limitation, website templates, flash templates, and brochure design templates;
(b) display the Content on websites designed to induce sales of "print on demand" products, including postcards, mugs, t-shirts, posters and other items (this includes custom designed websites as well as sites such as Cafe Press (i.e. www.cafepress.com));
(c) use the Content in any posters (printed on paper, canvas or other mediums) or other items for resale;
(d) use the Content or any part thereof as part of a trade-mark, design-mark, trade-name, business name, service mark, or logo;
(e) incorporate the Content in any product that results in a re-distribution of the Content (such as electronic greeting card web sites);
(f) use the Content in a fashion that is considered by iStock International Inc. (acting reasonably) as pornographic, obscene, defamatory or libelous in nature;
(g) use any image in the Content that depicts a person to endorse a business, product or service;
(h) use any image in the Content that depicts a person in a potentially sensitive subject matter, including, but not limited to mental and physical health issues, social issues, contraband or crime;
(i) to the extent that source code is contained within the Content or accompanying materials (if applicable), reverse engineer, decompile, or disassemble any part of such source code;
(j) remove any notice of copyright, trade-mark or other proprietary right from any place where it appears on or in the Content or its accompanying materials;
(k) sub-license, re-sell, rent, lend, or otherwise distribute the Content;
(l) post a copy of the Content on a network server or web server for use by other users; or
(m) transfer the rights to the Content or accompanying materials (if applicable), except as specifically provided for elsewhere in this Agreement.