It is possible to display a transparent image by using a UIAxes object and by making sure to retain the alpha data when reading and displaying the image. The code bellow shows an example on how this can be achieved:
fig = uifigure;
ax = uiaxes(fig);
[imdata, ~, imalpha] = imread('myimage.png');
image(imdata, "AlphaData", imalpha, "Parent", ax);
ax.Visible = "off";
It is then possible customize the axes further (for instance "ax.Position" allows to set the positions and dimensions of the image). The following page of the documentation lists the UIAxes properties that can be used:
https://www.mathworks.com/help/matlab/ref/matlab.ui.control.uiaxes-properties.html
