Uploaded images displayed after a few minutes

Hello!

I have created a script for uploading photographs with size less than 50 KB.
Everything works fine, but the images are viewable after a not so long time, but not at once. I would like to have the photographs available just after successful upload. Can you tell me, maybe there is some way to do that? Is it a my hosting server fault?

Thank you in advance
Marcin from Poland

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