Spatial transcriptomics technologies aim to localize gene expression in tissues and typically use capture surfaces that have undergone spatial indexing or optical decoding to relate surface sequences to spatial positions. Slide-tags is a recently developed method by Russell et al. that inverts this principle, instead diffusing probes from a pre-decoded bead array into tissues, tagging nuclei with spatial bead barcodes. We reanalyzed this data and discovered a latent, spatially informative cell-bead network formed incidentally as a result of barcode diffusion and the biophysical properties of the tissue. By optimizing proximity constraints encoded in the cell-bead network structure, we could infer cell locations without any spatial indexing, placing Slide-tags among a new generation of optics-free, network-based imaging-by-sequencing approaches, a fundamental departure from classical spatial sequencing technologies based on pre-indexed arrays.