asking for "technique issue"

[종승]

Hi.

I've got to know about the "stock" yesterday and uploaded few pics of mine.
Almost of them has bad resolution, so I used photoshop to improve it more than 4mp.

As you can guess, those all pics are rejected by technique issue.

This "a stretch" improvement of resolution can affect to technique issue rejection?

[tiger622010]

If the already have bad resolution that using a software to try to repair them will not do well as you have found out. I try my best to make a good photo in the camera first and than use a software program only to address small cosmetic things.  You're going into a very mature business with lot's of professional images to compete. Only the best images will go on to sell. 

[종승]

then only in case that origin picture's resolution is good can be not rejected?

is there any other possible causes which can make technique issue reject?

[Abambo]

There are many reasons to reject an image.

If you are new to stock, you should consider these resources: https://helpx.adobe.com/stock/contributor/tutorials.html
Please read the contributor user manual for more information on Adobe stock contributions: https://helpx.adobe.com/stock/contributor/user-guide.html
See here for rejection reasons: https://helpx.adobe.com/stock/contributor/help/reasons-for-content-rejection.html
and especially quality and technical issues: https://helpx.adobe.com/stock/contributor/help/quality-and-technical-issues.html

[Abambo]

Pictures that do not meet the required minimal resolution should not be uploaded. Upsizing is clearly a refusal reason.

Upsizing does not enhance the resolution of the picture, it just adds pixels. In most cases, the picture gets less sharp and artefacts get amplified.

[Nancy OShea]

You cannot make a silk purse from a pig's ear.   DO NOT upsize low resolution images. 

What kind of camera do you have?

[종승]

I'm using sony a6000 (ILCE-6000) with its bundle lense(16-50)

After I read replies, I found that origin raw files and its retouched version has enough resolution(almost 24mp).

I think resolution drop has occurred while I change my storage location.(those pics were uploaded to my messenger app's cloud storage for easy uploading to my instagram).

My bad 😞