Text-to-image (T2I) systems enable rapid generation of high-fidelity imagery but are misaligned with how visual ideas develop. T2I systems generate outputs that make implicit visual decisions on behalf of the user, often introduce fine-grained details that can anchor users prematurely and limit their ability to keep options open early on, and cause unintended changes during editing that are difficult to correct and reduce users' sense of control. To address these concerns, we present Creo, a multi-stage T2I system that scaffolds image generation by progressing from rough sketches to high-resolution outputs, exposing intermediary abstractions where users can make incremental changes. Sketch-like abstractions invite user editing and allow users to keep design options open when ideas are still forming due to their provisional nature. Each stage in Creo can be modified with manual changes and AI-assisted operations, enabling fine-grained, step-wise control through a locking mechanism that preserves prior decisions so subsequent edits affect only specified regions or attributes. Users remain in the loop, making and verifying decisions across stages, while the system applies diffs instead of regenerating full images, reducing drift as fidelity increases. A comparative study with a one-shot baseline shows that participants felt stronger ownership over Creo outputs, as they were able to trace their decisions in building up the image. Furthermore, embedding-based analysis indicates that Creo outputs are less homogeneous than one-shot results. These findings suggest that multi-stage generation, combined with intermediate control and decision locking, is a key design principle for improving controllability, user agency, creativity, and output diversity in generative systems.

翻译：文本到图像（T2I）系统能够快速生成高保真图像，但与视觉创意的自然发展过程存在偏差。T2I系统在生成输出时会隐式替用户做出视觉决策，常引入精细细节而过早固化用户思路，限制其在创意初期保持选项开放的能力；同时，编辑过程中产生的非预期变更难以修正，削弱了用户对系统的掌控感。为解决这些问题，我们提出Creo——一种多阶段T2I系统，通过从粗略草图渐进到高分辨率输出的方式支撑图像生成，并暴露中间抽象层级供用户进行增量修改。草图式抽象因其暂定性特征，既能引导用户参与编辑，又能在创意尚未成型时帮助用户保持设计选项的开放性。Creo的每个阶段均可通过手动修改与AI辅助操作进行调整，通过锁定机制实现细粒度的分步控制——该机制保留先前的决策，使后续编辑仅影响指定区域或属性。用户始终处于创作流程中，跨阶段进行决策制定与验证，而系统采用差异更新而非整体重绘图像的方式，随保真度提升减少漂移。与一次性基线系统的对比研究表明：参与者对Creo输出具有更强的归属感，因其能追溯自己在图像构建过程中的决策轨迹。此外，基于嵌入的分析显示，Creo输出的同质性低于一次性生成结果。这些发现表明：将多阶段生成与中间控制及决策锁定相结合，是提升生成系统可控性、用户能动性、创造力及输出多样性的关键设计原则。