Confluence text images are blurry

[siva]

Hello ,
In my confluence page we are using the image width max 1000px. So here the issue is few images with text content not visible properly and blury as well and if we convert to PDF that looks fine in PDF and this is only an issue online (exports to PDFs look fine) also if we clink on image the image popup comes that also look fine but not in page online.

But other few images with same text content and using same 1000px that looking fine only few got this issue and we are using confluence V7.13.2 and image PNG file. Please help me how to resolve this issue.

Thanks,
Siva.