You use a photo editor
Do 20% of original photo and that should knock even the biggest down to under 500kb's at least
I cant expalin it unless I sitting at "your" computor with you
Depends on what Editor you have access to - all smart phones have an Editor now and 90% of time pics are taken with same phone
Google some UTube demos
Plenty of Free to use Apps/Programs that can do it for computor
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