Hello Remya176,
Thank you for using Apple Support Communities. Based on your post, after updating your iPhone 8 to iOS 15 edited photos or photos taken with filters, do not appear correctly. We'll do our best to assist with this.
Are you using iCloud Photos? If so, go to Settings > [Your Name] > iCloud to make sure that Photos is currently enabled.
On another device, visit the iCloud website: Sign in to iCloud
Select Photos after signing in. Then check to see if these photos are showing up blank here or if they're showing up correctly.
Open up the Photos app on your iPhone 8. Look at the bottom of the main page, does it reflect that it's loading content to iCloud? If so, you may need to wait for it to complete the upload for these photos to show up properly for you.
If you end up not using iCloud Photos or these photos still appear to be on a blank page, then we'd recommend to contact Apple Support directly: Get Support
Wishing you well, take care.