ok, so it returns a base64 image string.
the image-tools "image" node can do the base64 to buffer conversion.
[{"id":"9e4c431727221940","type":"inject","z":"20165f674cef3579","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":1160,"y":700,"wires":[["61297201e8f2d924"]]},{"id":"61297201e8f2d924","type":"function","z":"20165f674cef3579","name":"simulate hik camera","func":"msg = {\n \"topic\": \"\",\n \"payload\": \"data:image/jpeg;base64,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\"\n}\nreturn msg;","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":1360,"y":700,"wires":[["62576c1c034bcb4c"]]},{"id":"62576c1c034bcb4c","type":"jimp-image","z":"20165f674cef3579","name":"base64 img to buffer","data":"payload","dataType":"msg","ret":"buf","parameter1":"","parameter1Type":"msg","parameter2":"","parameter2Type":"msg","parameter3":"","parameter3Type":"msg","parameter4":"","parameter4Type":"msg","parameter5":"","parameter5Type":"msg","parameter6":"","parameter6Type":"msg","parameter7":"","parameter7Type":"msg","parameter8":"","parameter8Type":"msg","sendProperty":"buffer","sendPropertyType":"msg","parameterCount":0,"jimpFunction":"none","selectedJimpFunction":{"name":"none","fn":"none","description":"Just loads the image.","parameters":[]},"x":1590,"y":700,"wires":[["04ba9b37ba13b900"]]},{"id":"04ba9b37ba13b900","type":"image viewer","z":"20165f674cef3579","name":"","width":160,"data":"buffer","dataType":"msg","active":true,"x":1310,"y":760,"wires":[["69957e686cdfa0f4"]]},{"id":"69957e686cdfa0f4","type":"change","z":"20165f674cef3579","name":"","rules":[{"t":"set","p":"topic","pt":"msg","to":"A new image...","tot":"str"},{"t":"set","p":"payload","pt":"msg","to":"See attached","tot":"str"},{"t":"set","p":"attachments","pt":"msg","to":"[{}]","tot":"json"},{"t":"set","p":"attachments[0].filename","pt":"msg","to":"image.jpg","tot":"str"},{"t":"set","p":"attachments[0].content","pt":"msg","to":"buffer","tot":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":1500,"y":760,"wires":[["cd6e6a759b81a782"]]},{"id":"cd6e6a759b81a782","type":"debug","z":"20165f674cef3579","name":"to email node","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":1720,"y":760,"wires":[]}]
