Abstract: Generative tools enable visual designers to rapidly explore diverse design directions---but as flawed generated outputs proliferate, designers may lose track of promising ideas and the context of their development. We introduce trinkets: user-preserved design elements that function as reusable materials, retrieval queries, and navigational anchors for tracing how ideas emerge, transform, and recur throughout design history. We implement this concept in Trinketry, a visual exploration canvas. In a within-subjects study with 12 concept designers, Trinketry supported focused element-level exploration and greater perceived control than a simple branching image generation history baseline. A follow-up study with six returning designers examined delayed design history sensemaking, continuation of work, and reconstruction of others' processes. Compared with whole-image histories, Trinketry supported more precise reconstruction of process structure, turning points, and goals, while helping designers recover overlooked materials and continue exploration. However, opportunities remain to augment trace representations with explicit statements of design rationale.