python - Crop an image, based on values -

i have multiple images, this:

orange represents values equal 0, white represent values equal 255, blue represents field, values vary 0 255. i rid of orange area, bit different in each image. best way that?

edit 1

i thought answer help: bounding box approach. except, array a_extract , not a_trim:

a = np.array([[0,   0,   0,   0,   0,   0, 0],               [0, 255,   0,   0,   0,   0, 0],               [0,   0, 255, 255, 255, 255, 0],               [0,   0, 255,   0, 255,   0, 0],               [0,   0, 255, 255, 255,   0, 0],               [0,   0,   0, 255,   0,   0, 0],               [0,   0,   0,   0,   0,   0, 0]])  a_trim = np.array([[255,   0,   0,   0,   0],                    [  0, 255, 255, 255, 255],                    [  0, 255,   0, 255,   0],                    [  0, 255, 255, 255,   0],                    [  0,   0, 255,   0,   0]])  a_extract = np.array([[255, 255, 255],                       [255,   0, 255],                       [255, 255, 255]) 

so basically, code should found bounding box, elements in first , last row (as in first , last column) should have same value (e.g. 255).

edit 2

the real image classified satellite image, stored numpy array (with shape cca. 7000x8000) , not rgb image. how looks like:

• orange = 0
• green = 2
• pink = 3
• white = 255

the aim rid of 0 values on edges.

the image posted has white border black lines on 3 sides before orange.

this remove white border change orange white:

 convert amgch.png -trim -fill white -draw "color 5,5 floodfill" output.png