Behold, an image of the pre-dynastic king Narmer, perhaps around 3100 BC: https://www.britishmuseum.org/collection/object/Y_EA35714. Behold also an image of Ptolemy XII Auletes, 3000 years later: https://buffaloah.com/a/virtual/egypt/philae/outer/source/13.html. As you can hopefully see, other than the iconographic change of crown, from Narmer’s hedjet (white crown) of Upper Egypt to Ptolemy’s atef, the images are remarkably similar, with very little change in body type or facial appearance. The image – or better, iconography, the way of representing – the Egyptian king broadly changed very little over time: it is in many ways better to think of the king as distinct from the person occupying the role. In much the same way as multiple actors have played Spiderman, but all ultimately look identical under the mask, the king was a fundamental part of Egyptian life and their understanding of themselves; the person or body of the king was distinct from the king themselves, and the latter was what was depicted. This is clear also from Egyptian texts, in which we rarely find ‘the King said ...’ and more often find ‘the Person of the King said ...’ or ‘his/her Person said ...’.

Nonetheless, while this holds true generally, there were exceptions when certain kings chose to modify this typical iconography. One very noticeable example is Senwosret III (around 1850 BC), whose statues blend the traditionally youthful and muscular body with a somewhat worn and tired face, and very big ears (e.g. https://www.metmuseum.org/art/collection/search/544186). Earlier and more basic analyses saw these as a move towards ‘realism’, though why the king should break from tradition for the sake of ‘realism’, and why he wouldn’t also do the same with his body, has not been satisfactorily explained; more likely is that he chose to emphasise certain ideological aspects of kingship, in particular his ability to hear and properly answer legal cases, in addition to the strong and powerful physical abilities of the king. Original statues of this type would presumably have been made at the Residence (the royal court) and disseminated across Egypt to the most important cult sites, where they could be copied if necessary.

More famous are the examples of Hatshepsut and Akhenaten (15th-14th centuries BC). Hatshepsut’s path to the kingship was not straightforward: she was the Chief Wife of her brother Thutmose II, then after his death Queen Regent for his son by a minor wife, and then eventually became king in a co-regency with her nephew. Before assuming the kingship her iconography is traditional for an Egyptian royal woman; after becoming king she adopts many of the traditional elements of the king’s iconography (cf. what I was saying above about the kingship being something of a costume) with a feminine body; the feminine aspects are generally, but neither entirely nor consistently, removed from her image throughout her reign. Compare https://commons.wikimedia.org/wiki/Category:Statues_of_Hatshepsut_in_the_Metropolitan_Museum_of_Art#/media/File:Hatshepsut_1.jpg, depicting the king with fairly pronounced breasts, with e.g. https://commons.wikimedia.org/wiki/Category:Hatshepsut_Kneeling_JE_53115#/media/File:By_ovedc_-Egyptian_Museum(Cairo)_-_128.jpg, with both the royal beard and a more masculine torso.

Akhenaten’s changes to the royal iconography were more pronounced, though were really an (admittedly very drastic) escalation of artistic changes taking place throughout the reigns of preceding rulers. The changes are characterised by, essentially, elongation: the face, hips, and belly are all stretched to increased length/breadth/depth. The overall effect is that the king appears with a more feminine – though still absolutely masculine – body. The reasons for this change are not immediately obvious: as with Senwosret III early analyses again decided on ‘realism’, perhaps because the king had some weird genetic disease or some other ridiculous reason. More recent arguments, which are considerably better, see these changes as reflective of Akhenaten’s reforms to the entire country, particularly his focus on the centrality of the king. Akhenaten weakened many of the most important temples and built a new capital close(r) to the geographical centre of the country; his religious reforms emphasise the unique ability of the king and his family to interact with the newly powerful Aten (sun-disc); the increased complexity of gender in his statuary should be seen as an attempt to reinforce his control over both men and women, as opposed to his largely masculine predecessors. These changes would have been agreed by the artists and writers at the royal court; for significant building works or decorations around the country, the king would send out these artists to the various temples to oversee and guide the project; local elites would then be able to adopt this iconography in their own private inscriptions. Akhenaten’s reign was not long, but his reforms were clearly emphatic: although later kings broadly returned to the iconography of earlier kings, many of the ratios and proportions used to design bodies during Akhenaten’s reign were maintained, albeit to a lesser degree.