Of course it's normal. Nowadays it's widespread. Pictures are altered more than words. Airbrushing etc. etc.
It's not down to the fact it's done, as I said it's done all the time and now even more so.
Political photos, t'v you name it. It's obvious. The why is so simple I fail to see how anyone could not be aware of it.
This is why there is a line between fiction and non-fiction.
Altering photos that purport to be accurate representations of actual events is emphatically NOT "normal." Any reputable news organization will fire people who do it.
Advertising photos, in contrast, exploit all the tools of the photographer's art -- electronic or not -- to present a very carefully manicured image.
For this reason, it's important to be clear about whether a particular image purports to be a historical record or not. Is it your position that publications officially approved by the Aikikai are advertising materials, are seen as such by the Aikikai, and should be interpreted as such by the aikido community?