How do I fade images without using gradient?

[Sins]

Do you guys have any modifications or techniques that you could recommend?

[Pixey]

I will assume you mean the 'edges' and not the whole image?

 

I sometimes lower the Opacity - Alpha in the color's window and then use the erase brush

[toe_head2001]

I've used this plugin in the past:

https://forums.getpaint.net/topic/26479-trs-edge-fader-extreme/

[ardneh]

Alpha Blur plugin.

 

Or, make a frame on a new layer, blur it, use it as a mask applied with the Paste Alpha plugin.
 

[BoltBait]

36 minutes ago, ardneh said:

Or, make a frame on a new layer, blur it, use it as a mask applied with the Paste Alpha plugin.

 

I would do it this way.