You've posted four pictures. Please take us through each one: how you made it, the app used to view it, and any problem you see, and where to look for the problem. Designers see their own issues very quickly, but it's hard when we're outside your process...!
So the images are the outcome when you increase the font size. is there a way that when i increase the font size, the image wont be cut?
The reader controls the font and the font size in Reflowable ePubs. Images must be anchored to the text and they resize automatically to match the screen size.
It's important that you validate your ePub and test it on a anumber of devices and readers.
Without more information, based on the images that @nickpua2 posted, I would surmise that the reader used is the culprit: it is cutting off the image. Check the reader settings, and test in an alternative reader such as Thorium (https://www.edrlab.org/software/thorium-reader/).
In Thorium the layout is adjustable to either a scrolling page or a paginated one. In Thorium's case the image is moved to the next page when it does not fit. I am unsure about the Apple reader, since I currently have no direct access to a Mac.
But we really cannot be certain wihout knowing whether the file was exported as fixed epub, reflowable, and so on.