Development of laser-plasma X-ray sources provides a new route to high brightness and small source size somewhere in the middle of low cost micro-focus X-rays and large scale synchrotron facilities. We explore one application of this new type of sources with emphasis on the stability of the source at high repetition rate and the advantage over similar conventional sources. In this paper we report the development and application of a micro-focus X-ray source for phase contrast imaging. The X-ray source produced at the Laser Laboratory for Acceleration and Applications (L2A2) of the University of Santiago de Compostela (USC), is made by focusing a 1 mJ, 35 fs, 1kHz pulses at 800 nm wavelength on metallic plates close to the diffraction limit. The X-ray spectra of this source are characterized by the K-α peaks which can be 'tuned' by changing the target material and a Bremsstrahlung continuum up to several tens of keV. The stability of the source is achieved by optimizing the positioning system of the metallic target which refresh and keep the surface within the small the Rayleigh length allowing the development of applications.