# Writing an image using file node and a binary buffer
**URL:** https://discourse.nodered.org/t/writing-an-image-using-file-node-and-a-binary-buffer/13942
**Category:** General
**Created:** [2 August 2019 15:08 UTC](https://discourse.nodered.org/t/writing-an-image-using-file-node-and-a-binary-buffer/13942 "2019-08-02T15:08:54Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@lucaDgt](https://discourse.nodered.org/u/lucaDgt)
#### Post date: [2 August 2019 15:08 UTC](https://discourse.nodered.org/t/writing-an-image-using-file-node-and-a-binary-buffer/13942/1 "2019-08-02T15:08:54Z")
Hi,
my flow is using the file node as output, to dump an image i am receiving by socket, so i am working with binary data and Buffer.
the node file is configured in overwrite mode, and binary encoding, without appending any \n character,
so i would expect that the length of my msg.payload should be the same as my file.
actually in msg.payload the binary buffer of the image is stored, in the node exactly before the file node i write the length of the payload:
```auto
node.warn("going to Dump image bytes: " + msg.payload.length)
```
it prints:
```auto
"going to Dump image bytes: 1573302"
```
but the file node saves on the file system: 1560204 bytes.
Why? and the image is corrupted obliviously.
thanks in advance
Luca
---
### Author:  [@Petta](https://discourse.nodered.org/u/Petta)
#### Post date: [22 January 2020 13:55 UTC](https://discourse.nodered.org/t/writing-an-image-using-file-node-and-a-binary-buffer/13942/2 "2020-01-22T13:55:52Z")
Hi.
I have a similar problem
Recieving data from socket and everything from byte 11 in file is not the same as what comes from stream.
---
### Author:  [@cymplecy](https://discourse.nodered.org/u/cymplecy)
#### Post date: [22 January 2020 15:49 UTC](https://discourse.nodered.org/t/writing-an-image-using-file-node-and-a-binary-buffer/13942/3 "2020-01-22T15:49:33Z")
Hi and welcome
What system are you running on - what version of Node-RED etc etc
Is the file your trying to write large?
---
### Author:  [@Petta](https://discourse.nodered.org/u/Petta)
#### Post date: [22 January 2020 16:00 UTC](https://discourse.nodered.org/t/writing-an-image-using-file-node-and-a-binary-buffer/13942/4 "2020-01-22T16:00:12Z")
here is the buffer:
[66,90,104,57,49,65,89,38,83,89,151,206,141,167,0,0,134,159,128,80,14,127,240,40,0,4,0,190,255,222,106,48,0,184,131,85,63,9,164,201,234,9,144,26,0,25,61,65,128,25,52,208,100,48,67,76,70,140,13,79,68,10,122,153,61,38,67,79,77,77,0,208,19,1,160,2,65,26,200,6,81,210,112,166,89,4,51,61,150,175,96,31,75,6,251,162,68,172,69,54,168,59,6,1,229,177,128,186,252,2,176,171,149,200,30,224,168,131,20,171,67,133,149,130,189,53,98,201,68,147,38,62,4,81,38,234,17,182,214,48,57,208,79,141,36,82,254,25,175,115,210,169,227,68,13,122,103,157,102,153,4,250,95,3,89,224,141,93,228,196,158,197,172,250,89,233,75,184,144,214,88,66,12,215,106,53,188,94,166,90,56,73,204,70,147,60,94,172,66,73,168,241,217,92,45,107,130,171,161,96,42,136,167,236,191,139,185,34,156,40,72,75,231,70,211,128]
Node red 1.0.3
Linux Debian 10
Node.js 6.13.2
The output from Filewriter says the same as the buffer read from the network stream
I strip tjhe first 4 bytes from the stream as the are the lenght of the buffer, the rest is supposed to be a bz2 file
```auto
[{"id":"db7cca2.dffc038","type":"debug","z":"958f84ab.d1a518","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","x":886,"y":44,"wires":[]},{"id":"c3aba263.b16cc","type":"file","z":"958f84ab.d1a518","name":"Create celox2.bz2","filename":"c:\\test\\celox2.bz2","appendNewline":true,"createDir":false,"overwriteFile":"true","encoding":"binary","x":637,"y":45,"wires":[["db7cca2.dffc038"]]},{"id":"863f9aa8.183f48","type":"function","z":"958f84ab.d1a518","name":"","func":"msg.payload = msg.payload.slice(4, msg.payload.length);\nreturn msg;","outputs":1,"noerr":0,"x":440,"y":47,"wires":[["c3aba263.b16cc"]]},{"id":"8b550368.55051","type":"tcp-client","z":"958f84ab.d1a518","action":"Listen","actionType":"str","host":"","hostType":"str","port":"payload","portType":"msg","datamode":"stream","datatype":"buffer","newline":"","xmlAttrkey":"$","xmlCharkey":"_","xmlStrip":false,"xmlArray":false,"xmlNormalizeTags":false,"xmlNormalize":false,"write":"","writeType":"str","topic":"test","name":"","debug":"all","x":254.5,"y":48,"wires":[["863f9aa8.183f48"]]},{"id":"64387411.66150c","type":"inject","z":"958f84ab.d1a518","name":"","topic":"","payload":"9999","payloadType":"num","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":96.5,"y":49,"wires":[["8b550368.55051"]]}]
```
---
### Author:  [@cymplecy](https://discourse.nodered.org/u/cymplecy)
#### Post date: [22 January 2020 16:17 UTC](https://discourse.nodered.org/t/writing-an-image-using-file-node-and-a-binary-buffer/13942/5 "2020-01-22T16:17:43Z")
1st thing I've noticed is the filename is a windows format but you said you are running on Linux
---
### Author:  [@cymplecy](https://discourse.nodered.org/u/cymplecy)
#### Post date: [22 January 2020 16:31 UTC](https://discourse.nodered.org/t/writing-an-image-using-file-node-and-a-binary-buffer/13942/6 "2020-01-22T16:31:19Z")
I used your buffer and directly injected it into your function node and then compared its output with the actual file and I can see it seems to deviate after the 6th byte - not got a clue at moment as to what is going on!
Even cutting the function node out and only sending 16 bytes - its deviating after the 53 59 bytes
```auto
[{"id":"b3adce26.3c2e","type":"debug","z":"3517604c.8ef54","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","x":670,"y":440,"wires":[]},{"id":"218eb06c.6c894","type":"file","z":"3517604c.8ef54","name":"Create celox2.bz2","filename":"/home/pi/celox2.bz2","appendNewline":true,"createDir":false,"overwriteFile":"true","encoding":"none","x":490,"y":440,"wires":[["b3adce26.3c2e"]]},{"id":"663fd446.f51e5c","type":"inject","z":"3517604c.8ef54","name":"","topic":"","payload":"[66,90,104,57,49,65,89,38,83,89,151,206,141,167,0,0]","payloadType":"bin","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":310,"y":440,"wires":[["9fd55654.5b72d8","218eb06c.6c894"]]},{"id":"9fd55654.5b72d8","type":"debug","z":"3517604c.8ef54","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","x":470,"y":500,"wires":[]}]
```
---
### Author:  [@cymplecy](https://discourse.nodered.org/u/cymplecy)
#### Post date: [22 January 2020 16:43 UTC](https://discourse.nodered.org/t/writing-an-image-using-file-node-and-a-binary-buffer/13942/7 "2020-01-22T16:43:26Z")
Switching encoding from binary to default gets rid of the issue on the 16 byte test sequence
---
### Author:  [@Petta](https://discourse.nodered.org/u/Petta)
#### Post date: [22 January 2020 17:16 UTC](https://discourse.nodered.org/t/writing-an-image-using-file-node-and-a-binary-buffer/13942/8 "2020-01-22T17:16:32Z")
Typical!
I thought that i'v tried that!
Works perfectly!
---
### Author:  [@cymplecy](https://discourse.nodered.org/u/cymplecy)
#### Post date: [22 January 2020 19:50 UTC](https://discourse.nodered.org/t/writing-an-image-using-file-node-and-a-binary-buffer/13942/9 "2020-01-22T19:50:07Z")
But it shouldn't do it so it needs further investigation
---
### Author:  [@Petta](https://discourse.nodered.org/u/Petta)
#### Post date: [9 March 2020 12:46 UTC](https://discourse.nodered.org/t/writing-an-image-using-file-node-and-a-binary-buffer/13942/10 "2020-03-09T12:46:24Z")
the mainsystem is on linux.
Forgot that i moved to a windowssystem to try it there also.