Hello All,
I need to use sliders and buttons as you can see at the attachment. However, I have a problem about transparent image. When I create a button at nextion editor, I choose image. Although the image is transparent, on the screen it seems with blue background. I have tried to use crop image. But crop image will make difficult my scenario. As I press the button, button level will change.
Could you please help me?
Thank you.

Hello ber2bingol.
Please read 'how to use this forum - please read', especially part 9 about inserting images.
Here is yours

The Nextion doe not support transparency (alpha) in images.
You can do an awful lot with cropped images, here is my heating controller. The photo shows the main screen (unfortunately with me reflected in it). The horizontal bars show the set temperature and the current temperature and are created using sliders with a cropped image for the background. The background is a photo of the Northern Lights (because I liked it).
If you want to know how to do that see my tutorial 'using Nextion displays with Arduino', there is an example of using cropped images in part 4.
Thanks for that ^
Any chance of a link to save me searching?
It is not available on all displays.
You need the new intelligent series AND you must be aware the arduino library has not been updated.
Nevertheless... the new display offer a great set of new features.
The extract above is from nextion site.
Cheers