This study investigates the strategic adjustments in visual infographic designs employed by government agencies on social media and their effects on communication effectiveness and audience engagement. A total of 658 visual infographics published by Taiwan’s Agriculture and Food Agency on its official Facebook page between 2021 and 2023 were analyzed using a mixed-methods approach combining qualitative and quantitative research. Initially, expert focus groups were conducted to categorize infographic designs into six distinct types: interactive, illustrative, comparative, relational, schematic, and composite infographics. Subsequently, quantitative analyses of audience reach and engagement rates for each infographic type were conducted to identify annual shifts in audience preferences. The findings indicate: (1) a clear strategic evolution in infographic design types, showing an increasing diversification over time; and (2) a progressive yearly improvement in the overall effectiveness of visual infographics. Specifically, audience reach preference shifted from initially favoring relational and interactive types toward schematic, comparative, and illustrative types, characterized by clarity and simplicity. Audience engagement transitioned from an early emphasis on interactive infographics towards relational and illustrative types, ultimately preferring composite infographic types. These trends demonstrate that audience preferences are moving toward diversified information needs and integrated visual presentations. This research provides practical and actionable recommendations for infographic design that aim to enhance visual communication effectiveness and audience interaction on governmental social media platforms, facilitating broader and more impactful dissemination of public policy information.