You might look at the css at top of the page in code view. I have had trouble where it says display=block, so you might save a copy aside and then delete anything saying display in the css of the copy and see what you get.
Be aware that if the images are in fact really small, if you succeed in making them bigger they may turn pixelated and jagged. The only cure for that is find another source for bigger images.
You might also look at the css for anything regulating the paragraphs, since the picture is in a paragraph <p>. You could alter the css if it is a problem or simply put in a <br/> before and after in lieu of the <p>.