The main item image on the item page takes quite some time before it appears in the epsilon theme.
At first, I thought the issue has to do with hosting until I decided to test your demo.
I compare the Veronika theme and Epsilon and it is clear that the image lags on the Epsilon theme.

I used these items from different themes:

Epsilon  - https://epsilon.mb-themes.com/for-sale/cameras-camera-accessories/canon-pix-z9_i77
Veronika - https://veronika.mb-themes.com/for-sale/electronics/canon-powershot-g7-x-i134
Delta - https://delta.mb-themes.com/for-sale/computers-hardware/imac-pro-i7-2-8ghz_i820

I have noticed that the Epsilon theme seems to load all Google Ads before showing the item image, hence the delay.
Please check.

@bemtele

Switching off lazyload in theme settings could help

@bemtele
Epsilon & delta use same lazyloader, it always wait until site is completely loaded and then go for images.
Maybe removing lazy class on content elements those are above page fold would help, but at same time google rankings may not think the same

@bemtele
Epsilon & delta use same lazyloader, it always wait until site is completely loaded and then go for images.
Maybe removing lazy class on content elements those are above page fold would help, but at same time google rankings may not think the same

Yes I know disabling lazy load will solve this but doing so will affect site performance in google eye.

My problem is that lazy load is enabled in other themes, especially the veronika theme but the image loading even though delayed is very optimal. The time, however, to call the images in Epsilon is somehow long. Even if my data network is in the best coverage loading images is still delayed. but when switching to veronika with lazy load enabled, the image loads faster.

Epsilon may use different lazyload library, it probably cannot be affected. Simply triggered when page finished loading.