Display screen or portion thereof with an animated graphical user interface

FIG. 1 is a front view of a display screen or portion thereof with an animated graphical user interface showing the claimed design;

FIG. 2 is a second image thereof;

FIG. 3 is a third image thereof;

FIG. 4 is a fourth image thereof;

FIG. 5 is a front view of a second embodiment of a display screen or portion thereof with an animated graphical user interface showing the claimed design;

FIG. 6 is a second image thereof;

FIG. 7 is a third image thereof; and,

FIG. 8 is fourth image thereof.

The broken lines in the figures show portions of the graphical user interface that form no part of the claimed design. The white surrounding the broken lines from no part of the claimed design.

The appearance of the animated image sequentially transitions between the images shown in FIGS. 1 - 4 and 5 - 8 . The process or period in which one image transitions to another forms no part of the claimed design.