The North Korean leader's visit was broadcast on state media a day after US Defence Secretary James Mattis said the US would "never accept" a nuclear-armed North Korea.
Ms Kim meanwhile can not be identified in the photographs, but the report by state news agency KCNA mentioned she was present along with other top officials.
It's unclear exactly when the images were taken, as they were released without a date.
A smiling Kim was captured inspecting a range of cosmetic products including soap and women's perfume alongside Ri, in her second public appearance this month. Known to be handling the party's propaganda operations, Yo-Jong has been seen accompanying Kim closely and in a casual manner - rare among the country's top officials - at high- profile public events.
Kim toured the Pyongyang Cosmetics Factory with other senior officials, according to a report published by KCNA, the state news agency.
The cosmetics apparently met with the approval of the rogue state's leader, who told it to produce world-class products, the BBC reported.
"The variety of cosmetics produced by the factory are numerous and qualitative, and that not only the pattern of their vessels but the packing boxes are very nice", Kim said.
"This can help women fulfil their dreams of becoming more handsome".
The Chinese appear to suspect North Korean dictator Kim Jong Un isn't done murdering his relatives. Her exact age is unknown and she rarely makes public appearances.
"As we intensify our efforts to counter North Korea's nuclear threats, we must consider the full array of policy options at our disposal", Royce, the committee chairman, said.
Though he is better known for his photo ops at military installations and missile test sites, Mr Kim's visit to a cosmetics factory serves an important propaganda goal in telegraphing the legitimacy of Mr Kim's rule to the Pyongyang elite and middle-class.