Choosing stock images for compositing is nothing like choosing stock images for a blog post or a presentation. You’re not looking for the prettiest image — you’re looking for images that will work together technically. I’ve bought thousands of stock images over the years, and most of the time I spend in stock libraries is rejecting images, not selecting them.

Here’s what I evaluate before downloading anything.

Light Quality and Direction

This is the first filter and it eliminates the most candidates. The lighting on any stock element must be compatible with the lighting in your scene.

Before browsing stock, I know exactly what I need: the light direction, whether it’s hard or soft, the approximate color temperature, and the intensity relative to the shadows. I reject anything that doesn’t match within a reasonable margin.

Flat, overcast lighting is the most forgiving for compositing because it creates minimal directional shadows and can be adapted to many scenes. Strongly directional lighting is useful when it matches your scene precisely but limits your flexibility.

Camera Angle and Perspective

A stock element photographed from below cannot be convincingly placed into a scene shot from above. Before downloading, I check whether the camera angle matches my background plate.

For objects, look at the visible faces — can you see the top of the object? You’re looking down at it. Can you see underneath? You’re looking up. The amount of foreshortening tells you the angle.

For people, the position of the eyes relative to the shoulders, the visible amount of the top of the head versus the underside of the chin — these all indicate camera height.

Resolution and Detail

Your stock elements need to hold up at the final output resolution of your composite. An element that looks fine as a thumbnail will reveal compression artifacts, noise, and softness when scaled to fill a significant portion of your canvas.

I look for:

• Clean edges: Zoom in on the element boundaries. Are they sharp and well-defined, or mushy from compression or poor focus?
• Noise levels: Open the darkest areas at 100%. Heavy noise in the shadows limits your ability to adjust the image without introducing artifacts.
• Compression: JPEG artifacts around edges are a nightmare for masking. Higher quality source files give you cleaner extractions.

Whenever possible, buy the highest resolution available. You can always downscale for a smaller composite, but you can’t manufacture detail that isn’t there.

Isolation Potential

How easy will this element be to extract from its background? Some stock images are compositing-ready; others will cost you hours of masking work.

Best case: Clean, contrasting background with clear separation between subject and background. A product on white, a person on a solid color backdrop.

Acceptable: Subject against a relatively simple background where edges are clearly defined. Minor background complexity that select-and-mask can handle.

Avoid: Subject against a busy background with similar colors to the subject. Fine details like hair blending into a similarly-toned background. Transparent or reflective objects on patterned surfaces.

The time you save by choosing easy-to-extract stock images pays for the premium price of better-shot elements. A cheap image that takes two hours to mask is more expensive than a quality image that takes ten minutes.

Image Format

When you have the choice, download in the largest, least-compressed format available. RAW files from stock libraries are rare but valuable — they give you the most adjustment latitude. TIFF is the next best option. High-quality JPEG is acceptable for most work but limits your ability to push exposure and color adjustments.

PNG files with transparency are ideal when available, as they eliminate the masking step entirely. Some stock libraries offer pre-extracted elements specifically for compositing.

Building a Personal Library

Over time, I’ve built a personal library of stock elements organized by category: skies, textures, people, objects, environments. When I find a high-quality element with good lighting and clean edges, I download it even if I don’t need it for a current project.

Having a curated library means I spend less time searching during active projects and more time compositing. I tag images with lighting direction, quality, and perspective to make finding compatible elements faster.

Stock selection is where the composite succeeds or fails. Spend the time here, and the assembly becomes dramatically easier.