Well...
it's not a plugin OR an action (unless you want to record this...) but here are some steps you can try (Ill base this on a portrait type image):

1. Open an RGB file.
   Add a background for your painting (Id used neutral background colors to provide contrast with the image)

SIDE NOTE: Applying a filter often yields a programmed (automatic) look to your image. Even if you are applying to a scan of a painting that you painstakingly built up brush stroke by brush stroke. To mitigate this apply filters and erase some of their effects with a semitransparent eraser.

2. Choose Layer -->Duplicate Layer

3. Select Filter -->Artistic --> Fresco

4. Adjust settings to;
   a. Brush Size 2
   b. Brush Detail 8
   c. Texture 2

5. Click OK

6. Choose Filter --> Fade Fresco

7. Leave Opacity at 100% but change Mode to Overlay

8. Select the Eraser (press E)

9. Set Opacity to 50% and make Wet Edges active

10. Select the 35-pixel diameter brush

Play around erasing away some of the Fresco filter layer. Change the Opacity settings for the brush as well as the Size to give a more varied appearance to your strokes, overlap and vary the length and direction as well.

11. Save your work and make a copy

12. Flatten all the layers on the COPY

13. Choose Filter --> Texture --> Texturizer

14. In the dialog box adjust settings:
    d. Texture: Canvas
    e. Scaling: 100%
    f. Relief: 2
    g. Light Direction: Top

15. Click OK

Bear in mind, Oil Painting is based on additive process the careful building up of strokes to achieve the interesting texture and complexity.

Play around with your image and have FUN

:)
retrocity