Task: Merge binary objects on multiple items into a single item

n8n workflow:
{"nodes":[{"id":"9d09405e-64a3-47ef-9d46-4942de51444b","name":"When clicking \"Execute Workflow\"","type":"n8n-nodes-base.manualTrigger","position":[400,460],"parameters":{},"typeVersion":1},{"id":"4fdc396b-07bd-471e-9e62-136300804809","name":"Set URLs","type":"n8n-nodes-base.code","position":[620,460],"parameters":{"jsCode":"return [{\n  json: {\n    url: \"https://static.thomasmartens.eu/n8n/file01.jpg\"\n  }\n}, {\n  json: {\n    url: \"https://static.thomasmartens.eu/n8n/file02.jpg\"\n  }\n}, {\n  json: {\n    url: \"https://static.thomasmartens.eu/n8n/file03.jpg\"\n  }\n}]"},"typeVersion":1},{"id":"17482568-2117-4a8c-a307-ebf30dc9c560","name":"HTTP Request","type":"n8n-nodes-base.httpRequest","position":[840,460],"parameters":{"url":"={{ $json.url }}","options":{"response":{"response":{"responseFormat":"file"}}}},"typeVersion":4},{"id":"de27f52b-8f7e-4b9c-a097-987db4cef5aa","name":"Merge items","type":"n8n-nodes-base.code","position":[1060,460],"parameters":{"jsCode":"let binaries = {}, binary_keys = [];\n\nfor (const [index, inputItem] of Object.entries($input.all())) {\n  binaries[`data_${index}`] = inputItem.binary.data;\n  binary_keys.push(`data_${index}`);\n}\n\nreturn [{\n    json: {\n        binary_keys: binary_keys.join(',')\n    },\n    binary: binaries\n}];\n"},"typeVersion":1},{"id":"539fe99d-c557-4e51-bc88-011fb604e1f3","name":"Sticky Note","type":"n8n-nodes-base.stickyNote","position":[580,320],"parameters":{"width":394,"height":304,"content":"## Example data\nThese nodes simply download some example files to work with."},"typeVersion":1},{"id":"710fd054-2360-447a-b503-049507c0a3b2","name":"Sticky Note1","type":"n8n-nodes-base.stickyNote","position":[1000,320],"parameters":{"width":304,"height":307,"content":"## Transformation\nThis is where the magic happens. Multiple items with one binary object each are being transformed into one item with multiple binary objects."},"typeVersion":1}],"connections":{"Set URLs":{"main":[[{"node":"HTTP Request","type":"main","index":0}]]},"HTTP Request":{"main":[[{"node":"Merge items","type":"main","index":0}]]},"When clicking \"Execute Workflow\"":{"main":[[{"node":"Set URLs","type":"main","index":0}]]}}}