Is there a filter that lets me make an image only have like 4 colours

[ADJ]

I am asking if there's a filter that lets you pick a number of colours and then the image changes to those few colours

 

 

Ex: I want an image to only have green, blue, purple and grey

[Welsh Yellow Cheddar]

Hello, 

There is the Quantize effect  that can reduce the number of colors but it doesn't give you an option to recolor it. You may need to use other plugins to change or replace the colors.

[Tactilis]

Welcome to the forums @ADJ

Please show us an example of your source image. The manner in which you can best reduce the number of colours to just a few will depend on the nature of the image.

[Pixey]

Hello @ADJ there is this Plugin where you can choose the amount of colors you want:

 

 

[frio]

There's TR's Custom Palette Matcher if you want to reduce to a specific set of colors, instead of having the colors automatically determined. It's very simple to use: make the palette you want using the paint.net palette swatch, save it, and by default those palettes are shown in the plugin's list. If your palette doesn't take up all the slots though you'll have to duplicate one of the colors to fill all the rest.

 

There's also QuantDith, which supports dithering while lowering color count to a specific palette. It does support the same paint.net palette files but the plugin has a crash bug: you must edit the palette text files (click the "open palettes folder" on the palette swatch window to find them) and remove the 2 empty trailing lines manually that paint.net adds - else the plugin explodes on trying to load the custom palette.

[BoltBait]

If you have my plugin pack installed, try:

 

Effects > Stylize > Floyd-Steinberg Dithering:

 

Select the "Use Current Palette" option then select the number of colors to use from the current palette.

 

You'll need to save the colors you want to use at the beginning of your palette before running the effect:

 

[MJW]

There's my plugin, Recolor Using Palette.