I am wondering why Silverstripe uses a resampled image instead of the original one, even though I did not edit or resize the image?
Silverstripe creates a _resampled folder in a subfolder of "assets" when I click on "insert image" in the TinyMCE rich text editor and chose a subfolder. In the TinyMCE input field it displays the correct image, but in the frontend on the actual public website it displays the resampled image (e.g. /assets/_resampled/ResizedImage200300-myimage.gif). I noticed a number of disadvantages for GIF images:
- transparent areas become black
- animated GIFs are static (first frame only)
- colours may appear wrong/dithered (probably the resampling may create a different colour index than the original one so that homogenous areas in one colour may be resampled with two colours, or two colours that look nearly identical may be resampled as colours with a higher contrast; this creates a pixelated effect)
- file sizes may be bigger (also for JPEGs)
I did not test PNG images yet but I guess there will be the same issues.
While the problems listed above may be hard to fix I do not see the need to use a resampled image if the image is not resized.
I will look into this further, but if anyone knows a way to force Silverstripe to use the original image I would be keen to know how.