Image function in R takes forever to run
===

I have a matrix of size 23,000 by 200 that was read in R as a dataframe but it takes a lot longer to process it than in MATLAB. 

For example in MATLAB I type `image(X)` and it takes less than a second, while in R takes ~ a minute to produce the image.

If I do `dim(X)`, it's the same story.

Any ideas why R may be handling such small matrix so inefficiently in comparison with MATLAB?

I like R a lot, just wondering about the possible sources of slow down.