portfolio section - images are blurry


I have a problem with my portfolio section. Images which I add to portfolio are blurry - have very bad quality.
Please take a look: www.bajtelfoto.pl
How I can resolve my problem ?

Hi there

markopopelko thank you for the question and hope you have a great day
i think i cant agree with you, to say honestly images have great quality and they are not blurry at all, maybe you can show me a screenshot or explain it differently?