- define "slow" - are we talking ~100ms? 1s+? 5s+? 10s+?
- what size image are you using?
- what is the source of the image?
- how often is it being called?
- is it necessary to access every pixel?
- Are you certain the slowness is from the image-tools node (perhaps if you are iterating every row and * column & the slowness is in your looping code)?
- where is node-red running? on on a raspberry PI? in docker? both? How much memory is available to the machine? (images, when decompressed to bitmap can be surprisingly large - hundreds of MBs)
can you post your flow or at least a screenshot & describe your process?
There may be better ways to achieve your goal that you havent considered?
Please note: The library underneath that node is