How to add color scale to a png file


#1

How can I add the color scale to a exist png image on the topright? The color scale is made by "KEGGprofile"
code is col<-col_by_value(temp,col=colorRampPalette(c('yellow','white','blue'))(1024),range=c(min(temp),max(temp))).
The temp data is:
Proteome Phosphoproteome
10365 0.1936665 0.8226708
3320 -0.6043064 0.3554265
596 -1.8526172 -0.4719894
6300 1.2375722 1.3151508
659 0.1260142 -0.6054770
858 -1.4846932 1.6420495

The png image is as follows:

I want the color scale at the topright of the image file, how to realize, thank you.