Technical requirements concerning image sizes, dimensions, file types accepted or specific subjects are different for each stock agency.
HINT: Some stock photo agencies ask you to pass a simple quiz before you can become a contributor in order to learn their requirements before you start submitting stock photos. Make sure your photo camera meets these requirements too, as most agencies do not accept image upsizing. Keep in mind that upsizing an image changes its size, but does not improve (and most likely reduce) its quality!
Technical Requirements: QUALITY is more than important
There is no point in uploading images that are out of focus, noisy, have bad composition, poor lighting and contrast. To be sure your photos meet technical requirements, check your images for the following common problems:
● Focus: any lens blur, camera shake or focus not where it should be. Usually it can be corrected afterwords with use of image editing software, but if affected, more likely your image will never be accepted for sale.
● Lighting: flat light, bad shadows and poor exposure are all serious flaws in an image. Stock images must be well lit and properly exposed to be useful in the most possible situations.
● Noise: if you end up with visible noise (for example due to high ISO in poor lighting conditions), carefully use noise reduction software. Incorrect use can lead to making your image worse than before you started.
● Compression: so called artifacts are an effect of in-camera compression to create JPG file or more likely over-processing your photo (using too excessive editing). To avoid this problem shoot with DSLR instead of “point and shoot” camera. Also, shoot RAW (it will give you more advanced image processing without loosing too much quality).
HINT: Do not sharpen too much as it may significantly affect your image quality.
● Chromatic aberration are recognized as purple (or blue/cyan/red/yellow) colored fringe or halo around the edges of your subject outlines. It is caused by the light passing through your lens not being focused on the camera sensor properly. You should remove it or at least reduce it with an image editing software. Please note that due to lens nature not all lens aberrations can be removed completely.
● Sensor spots and/or dead pixels: most of us have spots on our cameras’ sensors. These are dirt or particles that got into camera body and ended up on the sensor. They, along with dead pixels should be removed with editing software. Remember that reviewers check each image at 100% and will reject it if any spots are visible.
HINT: How to check if there are any spots on your camera sensor? Take a picture of an uniform background (grey or blue color preferably) with your lens closed down. The more you close down your lens, the more visible any dust on your sensor will be.
● Lens flare can make our shot amazing or destroy it completely. Most likely it will be the latter so avoid them if you can, unless you want to achieve specific effects.
● Series and/or similar photos of the same subject. To avoid it, shots should vary in composition, idea, lightning setup, camera angle, etc.
HINT: Avoid different software edits (such as, for example, different colour versions) of the same image, as it will be more likely rejected.
● Over-filtering is a common mistake because we would like our images to look like masterpieces. Unfortunately we forget that excessive filtering and manipulation can only do more harm.
HINT: Be very selective what filters you apply and how far you move the sliders. Designers look for something simple yet professional, so you have to learn how to balance it.
● Isolation: proper isolation of main object from background is one of the most difficult skills you should learn. Well isolated images are very useful for designers, who often do not want to spend their valuable time isolating it themselves.
HINT: If you use Photoshop, learn how to use pen tool to draw paths. It is a powerful tool used by professionals to isolate objects from background.