Update free_skymaps.adoc

Minor clarification on blender image compression.

src/docs/asciidoc/jme3/advanced/free_skymaps.adoc

@@ -68,7 +68,7 @@ The tutorial is in checklist format so you can mark items as you go to keep your
 - [ ] Slide the resolution scale to 100%.
 - [ ] In the Output panel change the image type to JPEG. I have found out by trial and error that using a JPEG file has the same image quality as a PNG or DDS file but with a huge difference in image size. A single PNG image will clock in at over 8mb to the JPEG size of 325kb. Even converting to a DDS file comes in at over 3mb for comparison (using RGB888 as is recommended by Momoko_Fan/Core Developer in this link:https://hub.jmonkeyengine.org/t/best-dds-format-for-skyfactory/17668/2[forum post]) with no gain in image quality that I could see. Your welcome to experiment on your own if you wish.
 - [ ] Set the image format to RGB.
-- [ ] Setting the quality slider to 0 has the effect of reducing the image size. In this example it reduced the image sizes to less than 125kb, once again with no discernable image degradation that I could see.
+- [ ] Setting the quality slider has the effect of reducing the image size where 0 is maximum compression and 100 is no compression. In this example, setting it to 0 reduced the image sizes to less than 125kb, once again with no discernable image degradation that I could see.
 
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 .World Tab