Cant upload new images on Minamaze theme

I’ve been trying to upload images for my website but I’m unable, feels like that, depending on the size of the image the media uploader is blocking the upload. As I did my research online, I heard it had to do with the functions.php. They even posted another code for the functions.php in which I updated and fixed the problem, BUT at the same time it broke my whole website, I couldnt even access it anymore. After fixing it I also saw a posting saying I had to update the file 02.homepage.php over lines 605, 611 and another I cant remember. The problem is, the file I have has only 375 lines I think, so I could not replace it. I dont know what to do anymore. Some images can be uploaded and other cant. My version Minamaze 1.0.5

Thanks

Thiago