It should be noted that in the photos above, the 1960 shot of demonstrators on a vehicle is taken from newsreel footage shown in Oshima Nagisa's 1960 film Cruel Story Of Youth (though I'm not sure if it is authentic or re-enacted), while a difference in the bus and crowd photos is that while the buses in 1980 were an integral part of the protest, in 1960, I imagine they were just 'bystanders'.
Additionally, both uprisings featured scenes like the ones below, but only the 4.19 uprising is documented by photos of police/soldiers firing on protesters , or retreating from protesters. Though soldiers opened fire on protesters, and were eventually forced out of the city during the Kwangju uprising, I've never seen photos or film of these events.
Of the two uprisings, Kwangju has been better documented (at least, at a glance, in English). Even if one searches the internet, much more documentary evidence is available about the Kwangju uprising (in both languages). While it could be simply that more people were filming the latter uprising, it may have more to do with two factors: Location and success (or lack thereof). The April uprising took place in Seoul and succeeded; the Kwangju uprising took place far from Seoul, in a long ignored region, and failed. Of course, the locations of these protests may have had a great deal to do with their success or failure. In 1960, the protests occurred at the centre, for all to see; in 1980, they occurred at the periphery, and what happened was essentially hidden for years, creating a need to catalogue the government’s crimes..
As this article describes April 1960,
President Rhee characteristically declared martial law. Troops and tanks were menacingly mobilized, but the troops under the tactical control of the United Nations Command were not issued live ammunition. When the Korean government publicly blamed the "devilish hands of the Communists" for the disturbances, the U.S. Secretary of State, Christian A. Herter, issued a statement that the United States believed "that the demonstrations in Korea are a reflection of public dissatisfaction over the conduct of the recent election and repressive measures unsuited to a free democracy."A protest at the centre of things certainly had its advantages, as perhaps did a more unequal relationship between Korea and an America which was increasingly fed-up with Rhee (Gleysteen did not mention the lack of live ammunition, but did suggest that Korean army leaders were “influenced to some extent by American views” in allowing their troops to side with the protesters). In considering the American response to Kwangju, the US Embassy only began to understand the seriousness of this ‘disturbance’ 3 or 4 days days after it began, after the military had opened fire and the protesters had begun to arm themselves, which presented a very different conflict than the 1960 uprising, when the military had a monopoly on lethal force. The official American statement of May 22, 1980 reads:
We are deeply concerned by the civil strife in the southern city of Kwangju. We urge all parties involved to exercise maximum restraint and undertake a dialogue in search of a peaceful settlement. Continued unrest and an escalation of violence would risk dangerous miscalculation by external forces. When calm has been restored, we will urge all parties to seek means to resume a program of political development as outlined by President Choi. We reiterate that the US government “will react strongly in accordance with its treaty obligations to any external attempt to exploit the situation in the Republic of Korea.”In considering how both of these uprisings played out, the role of the US seems necessary to consider, but it is only one of many considerations.
When examining the immediate success or failure of these uprisings, there is also the perception of success or failure to consider. The April uprising brought about democracy, but it was short-lived; 13 months of rudderless governing later, Park Chung-hee’s tanks rolled into Seoul. Despite its initial failure, it has been argued that Kwangju, over the long term, haunted Chun Doo-hwan’s presidency and may have kept the spark of protest alive until it re-ignited in 1987. The changing perceptions of these events, plus the fact that Kwangju remained unresolved for so long (and for some victims and their relatives, remains so) has likely helped keep the 1980 uprising in the public imagination 26 years later. Whether it will still remain there after 46 years, only time will tell.