Hello, does anyone know how to change the translation of the words highlighted in the attached screenshot? I can't find them anywhere ... Thanks

Theme translation file.

sorry, you are right. It had escaped me.
But do you by any chance know where I find this? If it can be translated ...

In osclass core.

nothing to do, I've searched everywhere but can't find it. Can you give me some more information? Thank you.

Not everywhere i guess or not close enough :-)
Text is in: oc-content/languages/en_US/core.po

Yes thats the core

In my core.po there is no translation of this sentence. Did you send me one of yours? So I see what line it refers to?

@vazzo

Line in original core is:

Click or Drop for upload images

Maybe an older version you have?

is the latest version. I bought it two days ago. But there is not!
If you send me a .po file of yours, I'll add it manually.

or at least the string to add
for example:

#: admin/configure.php:311
msgid "Cascading drop-downs"
msgstr "Drop-down a cascata"

(My .po file is translated into Italian)

the sentence I try to translate is:
"Drop files here to upload"

not

"Click or Drop for upload images"

@vazzo

Witch Osclass version do you use?

the last, 8.02

can you check oc-includes/osclass/frm/Item.form.class starting on line 1848 there should be next text if latest osclass is in use...
The text you are referring to is different but it's the only place where the text is set.... Correct me if i am wrong MB Themes. 
          text: {
            uploadButton: '<?php echo osc_esc_js(__('Click or Drop for upload images')); ?>',
            waitingForResponse: '<?php echo osc_esc_js(__('Processing...')); ?>',
            rotateButton: '<?php echo osc_esc_js(__('Rotate')); ?>',
            retryButton: '<?php echo osc_esc_js(__('Retry')); ?>',
            cancelButton: '<?php echo osc_esc_js(__('Cancel')); ?>',
            failUpload: '<?php echo osc_esc_js(__('Upload failed')); ?>',
            deleteButton: '<?php echo osc_esc_js(__('Delete')); ?>',
            deletingStatusText: '<?php echo osc_esc_js(__('Deleting...')); ?>',
            formatProgress: '<?php echo osc_esc_js(__('{percent}% of {total_size}')); ?>'
          }