Display screen or portion thereof with a graphical user interface

[0001]FIG. 1 is a front perspective view of a display screen or portion thereof with a graphical user interface, showing a first image in a sequence of our new design;

[0002]FIG. 2 is a front view showing a first image in a sequence thereof;

[0003]FIG. 3 is a front view showing a second image thereof;

[0004]FIG. 4 is a front view showing a third image thereof; and,

[0005]FIG. 5 is a front view showing a fourth image thereof.

[0006]The design sequentially transitions between the images shown in FIGS. 2-5. The process or period in which one image transitions to another image forms no part of the claimed design.

[0007]The inner broken line rectangle in the figures shows the display screen or portion thereof. Broken lines outside the display screen show the environment of a computing device. The remaining broken lines show portions of the graphical user interface. All broken lines form no part of the claimed design.

[0008]The broken box “capture” icon elements in the figures form part of the claimed design.