Graphical communication by students can provide important clues to teachers about misconceptions in fields like mathematics and computing. We have built a facility called INFACT-SKETCH that permits conducting experiments in the elicitation and analysis of studentdrawn diagrams. A goal of our project is to achieve the integration of a construction-oriented image processing and programming system with a combination of automatic and manual assessment tools in order to have a highly effective learning environment for information technology concepts. Some of the diagrams we elicit from students represent image processing algorithms, and others represent predictions of what particular mathematical formulas will do to images. In order to serve its educational assessment and research purposes, INFACT-SKETCH provides an unusual combination of features: tight integration with a web-based textual communication system called INFACT-FORUM, administrative control of which drawing tools students will be permitted to use (freehand, rectangles, ovals, text labels, lines, etc.), complete event capture for timed playback of the drawing process for any sketch in the system, graphical quoting option in message replies, and structured annotations for educational assessment. We describe the rationale, intended use, design, and our experience so far with INFACT-SKETCH.