how to save image in PLT - python

I'm trying to save my result image using matplotlib.pyplot as the following code which works good without any problem
import matplotlib.pyplot as plt
I = image.astype(np.uint8)
fig = plt.figure()
ax = fig.add_subplot(111)
ax.imshow(I)
plt.plot(marker_x, marker_y, color='yellow')# our circle
ax.set_title('Macula')
plt.savefig("J://uni//final project//res_image//marked_M.png")
fig.show()
here is my saved picture plt.savefig("J://uni//final project//res_image//marked_M.png") :
the yellow circle is a plot and as you know when we use plt.plot automatically we have a white space around the main picture (sth like margin as you see in the picture ) and also the axes
and its my 'tkinter' UI:
I'm wondering if is any way to crop this annoying white space or save image in another way that we get rid of this margin?


You can use the matplotlib transparent flag
plt.savefig("J://uni//final project//res_image//marked_M.png", transparent=True)
This will save the image as a png file with a transparent background

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You may specify the figure to which to plot with aplpy. You can then get the axes inside the figure.
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ok, this script give to me an image like this
so the next step is to put my dataset and not a random matrix, i know it, but I want to put some axis or text in this plot, and to get something like this image
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cheers

As #tcaswell said in the comments, the function you want to use is annotate, and the documentation can be found here.
I've given an example below using your code above:
import numpy as np
import matplotlib.pyplot as plt
def annotate_axes(x1,y1,x2,y2,x3,y3,text):
ax.annotate('', xy=(x1, y1),xytext=(x2,y2), #draws an arrow from one set of coordinates to the other
arrowprops=dict(arrowstyle='<->'), #sets style of arrow
annotation_clip=False) #This enables the arrow to be outside of the plot
ax.annotate(text,xy=(0,0),xytext=(x3,y3), #Adds another annotation for the text
annotation_clip=False)
fig, ax = plt.subplots()
image=np.random.rand(10,10)
plt.imshow(image)
plt.colorbar()
#annotate x-axis
annotate_axes(-0.5,10,4.5,10,2.5,10.5,'A') # changing these changes the position of the arrow and the text
annotate_axes(5,10,9.5,10,7.5,10.5,'B')
#annotate y-axis
annotate_axes(-1,0,-1,4,-1.5,2,'A')
annotate_axes(-1,4.5,-1,9.5,-1.5,7.5,'B')
plt.show()
This give the image shown below:

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Any suggestions?

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