The unique ClearSkies de-hazing algorithm works best on unprocessed imagery.
Try to use files that come directly from your data provider or camera in its original format,
with no color corrections or adjustments applied.
No borders please!
If your images have black or white "no-data" areas around the edges, try to remove these before uploading. You will notice inconsistent results with this type of image.
Play with the Adjustments
The ClearSkies process is "mathematically neutral". It aims to produce a result that may be used for scientific analysis. This does not (always) produce the best result for visual mapping. If your requirements are not technical, and you just want a nice looking image, feel free to play around with the adjustments menu until you get exactly what you are looking for.
Try the Compare menu
Clicking the "Compare" button will switch your view to an image comparison slider, where your before and after images are overlaid, and you can drag a control to examine the differences in detail.
Avoid "lossy" formats
Some image formats (particularly JPEG) have been preprocessed to make them smaller, at the loss of image quality. While these losses are often invisible to the naked eye, they can interfere with machine processing. Images are almost always originally captured in a lossless format. Try to use the original captured data whenever possible.